The Buddha condemned schism in strong terms, saying that a person who starts a schism knowing that he is not the side of the Dhamma is destined for hell immediately on his death (A.V.129). At the same time, the Buddha formulated two sanghadisesa rules (Sg 10 & Sg 11) to help intercept attempts at schism. He also gave special allowances for bhikkhus to try to prevent or end schisms, even if it means breaking their Rains-residence (see Chapter 11). Nevertheless, the Khandhakas do not depict him as discouraging people from taking sides in a schism. Instead, he instructs them to look into the matter and to side with the faction on the side of the Dhamma. He also does not encourage a too-hasty healing of the schism. If a split Community tries to patch up its differences without getting to the root of the matter, the transaction with which unification is announced is invalid, and the matter must be opened up again. Thus he does not advocate superficial harmony for its own sake, at the expense of the Dhamma, but instead encourages that the Dhamma be clearly defended against non-Dhamma, and that the distinction between the two be kept clear.
Behavior during a schism. When a bhikkhu has learned that a dispute has led to a schism, he is to side with whichever faction sides with the Dhamma. According to Mv.X.5.4, a speaker of non-Dhamma is to be recognized as such if he "explains not-Dhamma as 'Dhamma' ... Dhamma as 'not-Dhamma' ... not-Vinaya as 'Vinaya' ... Vinaya as 'not-Vinaya' ... what was not spoken, not mentioned by the Tathagata as 'spoken, mentioned by the Tathagata' ... what was spoken, mentioned by the Tathagata as 'not spoken, not mentioned by the Tathagata' ... what was not regularly practiced by the Tathagata as 'regularly practiced by the Tathagata' ... what was regularly practiced by the Tathagata as 'not regularly practiced by the Tathagata' ... what was not formulated by the Tathagata as 'formulated by the Tathagata' ... what was formulated by the Tathagata as 'not formulated by the Tathagata' ... a non-offense as 'an offense' ... an offense as 'a non-offense' ... a light offense as 'a heavy offense' ... a heavy offense as 'a light offense' ... an incurable offense as 'a curable offense' ... a curable offense as 'an incurable offense' ... a serious offense as 'a not-serious offense' ... a not-serious offense as 'a serious offense.'" A speaker of Dhamma is to be recognized as such if he explains not-Dhamma as "not-Dhamma," Dhamma as "Dhamma," and so forth.
Thus the ability to take sides requires that one be well-informed about the Buddha's teachings. If one cannot clearly judge which side is right (it might be that both sides are wrong, or that they have split over a gray area where the texts leave room for various interpretations), it is best not to get involved. Mv.III.11.5 gives permission for a bhikkhu to break his Rains-residence if bhikkhus in his Community are striving for a schism and he does not want to be present at the final break. Arguing from this allowance, it would make sense that if a bhikkhu arrives at a Community where the break has occurred and he does not want to get involved in it, he would do well to go elsewhere.
Bhikkhunis connected to a Community that has split should listen to both sides of the split and then give preference to whichever faction sides with the Dhamma. They should look to the Dhamma-faction for whatever services they expect from the Bhikkhu Sangha, such as the exhortation and the scheduling of the uposatha day (see Chapter 23). As for the laity, the texts quote the Buddha as saying that they should give gifts to both factions and listen to their Dhamma. Then, on consideration, they should give their preference to the Dhamma-faction. Notice, however, that in advising the laity to give preference to one faction over another, the Buddha does not say that only one faction should receive alms. After all, the laity may be misinformed about the Dhamma and in a poor position to tell the right faction from the wrong. At the same time, the Buddha has never been recorded as declaring a living being as unworthy of gifts, for that would be tantamount to saying that the being was unworthy to live. Still, there is the instructive tale contained in Mv.X, telling of a case where the Community in Kosambi split into two factions (without reaching the point of schism), with both sides citing the Vinaya to support their positions. After both sides had resisted the Buddha's efforts to settle their differences, he left Kosambi. The lay supporters then forced a settlement by refusing to give alms to either side.
Practicalities. With regard to lodgings, the two factions of the schism should be given separate lodgings, to minimize friction. However, this should be arranged so that worthy senior bhikkhus are not deprived of the lodgings they deserve. The commentaries give no advice as to what this means or how it should be arranged, but apparently if each faction contains senior bhikkhus, good lodgings should be given to both sides so that the senior bhikkhus will not be inconvenienced.
Offerings given to the Community should be shared between both factions. This principle holds regardless of whether the offerings were given before or after the split. Offerings given to a particular faction after the split are for that faction only.
Ending schism. A schism can be rightfully ended only if both sides are able to investigate the grounds (i.e., the point of dispute around which the schism crystallized), get to root (the mind-states motivating the schism -- see Cv.IV.14.3-4), and then come to a reconciliation based on the Dhamma and Vinaya. (See the instructions for settling a dispute in Volume One, Chapter 11.) After the issue has been resolved, all members of both factions are to meet: no one may send his consent, and even those who are ill must come to the meeting. One of the bhikkhus recites the transaction statement announcing the unification of the Community, and a harmony-uposatha is then held (see Chapter 15). That ends the schism.
This method works only in cases where both factions are acting in good faith, each believing that it has interpreted the Dhamma-Vinaya properly. In such cases, differences can be settled by appealing to bhikkhus whose knowledge of the Dhamma-Vinaya is authoritative. There are, however, cases where bhikkhus have started a schism with corrupted intent, in full knowledge of the fact that they are deviating from the Dhamma-Vinaya. In these cases, unification is well-nigh impossible. The best that can be attempted is to talk to those who have joined the schismatic faction out of ignorance and to win them over to the Dhamma side by explaining the true Dhamma-Vinaya to them. If they leave the faction and return to the Community, they are to confess a thullaccaya offense (Cv.VII.4.4), and they are full-fledged members of the Community as before.
Roots of disputes: three unskillful & three skillful
[A list is inserted giving six unskillful traits:] A bhikkhu who is:
1) easily angered & bears a grudge;
2) mean & spiteful;
3) jealous & possessive;
4) scheming & deceitful;
5) has evil desires & wrong views;
6) is attached to his own views, obstinate, unable to let them go.
Such a bhikkhu lives without deference or respect for the Buddha, the Dhamma, the Sangha; does not complete the training. When he causes a dispute in the Community, it comes to be for the harm, the unhappiness, the detriment of many people, for the pain and harm of human and divine beings. -- Cv.IV.14.3
Three unskillful roots: states of mind that are covetous, corrupt, or confused. Three skillful roots: states of mind that are not covetous, corrupt, or confused. -- Cv.IV.14.4
Ven, Sariputta: "How am I to behave with regard to these (schismatic) bhikkhus?"
The Buddha: "In that case, Sariputta, take your stance in line with the Dhamma."
Ven. Sariputta: "And how should I know what is Dhamma and what is not-Dhamma?" -- Mv.X.5.3
The Buddha: "There are these eighteen grounds by which a speaker of not-Dhamma is to be known. He explains not-Dhamma as 'Dhamma' ... Dhamma as 'not-Dhamma' ... not-Vinaya as 'Vinaya' ... Vinaya as 'not-Vinaya' ... what was not spoken, not mentioned by the Tathagata as 'spoken, mentioned by the Tathagata' ... what was spoken, mentioned by the Tathagata as 'not spoken, not mentioned by the Tathagata' ... what was not regularly practiced by the Tathagata as 'regularly practiced by the Tathagata' ... what was regularly practiced by the Tathagata as 'not regularly practiced by the Tathagata' ... what was not formulated by the Tathagata as 'formulated by the Tathagata' ... what was formulated by the Tathagata as 'not formulated by the Tathagata' ... a non-offense as 'an offense' ... an offense as 'a non-offense' ... a light offense as 'a heavy offense' ... a heavy offense as 'a light offense' ... an incurable offense as 'a curable offense' ... a curable offense as 'an incurable offense' ... a serious offense as 'a not-serious offense' ... a not-serious offense as 'a serious offense.' These are the eighteen grounds by which a speaker of not-Dhamma is to be known. -- Mv.X.5.4
"There are these eighteen grounds by which a speaker of Dhamma is to be known. He explains not-Dhamma as 'not-Dhamma' ... Dhamma as 'Dhamma' ... not-Vinaya as 'not-Vinaya' ... Vinaya as 'Vinaya' ... what was not spoken, not mentioned by the Tathagata as 'not spoken, not mentioned by the Tathagata' ... what was spoken, mentioned by the Tathagata as 'spoken, mentioned by the Tathagata' ... what was not regularly practiced by the Tathagata as 'not regularly practiced by the Tathagata' ... what was regularly practiced by the Tathagata as 'regularly practiced by the Tathagata' ... what was not formulated by the Tathagata as 'not formulated by the Tathagata' ... what was formulated by the Tathagata as 'formulated by the Tathagata' ... a non-offense as 'a non-offense' ... an offense as 'an offense' ... a light offense as 'a light offense' ... a heavy offense as 'a heavy offense' ... an incurable offense as 'an incurable offense' ... a curable offense as 'a curable offense' ... a serious offense as 'a serious offense' ... a not-serious offense as 'a not-serious offense.' These are the eighteen grounds by which a speaker of Dhamma is to be known." -- Mv.X.5.5
Mahapajapati Gotami: "How am I to behave with regard to these (schismatic) bhikkhus?"
The Buddha: "In that case, Gotami, listen to the Dhamma from both sides. Having listened to the Dhamma from both sides, give preference to the view, persuasion, preference, and belief of the side of those who speak Dhamma. And whatever the Community of bhikkhunis expects from the Community of bhikkhus should all be expected from the side of those who speak Dhamma." -- Mv.X.5.7
Anathapindika (and Visakha): "How am I to behave with regard to these (schismatic) bhikkhus?"
The Buddha: "In that case, householder, give gifts to both sides. Having given gifts to both sides, listen to the Dhamma from both sides. Having listened to the Dhamma from both sides, give preference to the view, persuasion, preference, and belief of the side of those who speak Dhamma." -- Mv.X.5.8 (9)
Ven. Sariputta: "How am I to act with regard to their lodgings?"
The Buddha: "In that case, Sariputta, separate lodgings are to be given to them."
Ven. Sariputta: "And if there are no separate lodgings, what should I do?"
The Buddha: "They are to be given after having made them separate. But in no way do I say that a lodging should be withheld from a more deserving (senior) bhikkhu. Whoever should withhold it: an offense of wrong doing."
Ven. Sariputta: "And how am I to act with regard to material gifts?"
The Buddha: "Material gifts are to be shared equally among all." -- Mv.X.5.10
"There is the case where bhikkhus have spent the Rains and the Community splits before robe-cloth arises. People give water to one faction and robe-cloth to the other faction, saying, 'We are giving to the Community.' That is for the (entire) Community. ... People give water to one faction and robe-cloth to the same faction, saying, 'We are giving to the Community.' That is for the (entire) Community. People give water to one faction and robe-cloth to the other faction, saying, 'We are giving to the faction.' That is just for the faction. People give water to one faction and robe-cloth to the same faction, saying, 'We are giving to the faction.' That is just for the faction." -- Mv.VIII.30.4-5
"There is the case where bhikkhus have spent the Rains and, when robe-cloth has arisen but before it is divided, the Community splits. That is equally for all." -- Mv.VIII.30.6
Procedure for achieving unity in the Community: "One and all should gather together, the ill and the not-ill. Consent is not to be conveyed for anyone." Transaction statement. "Immediately the uposatha is to be done, the Patimokkha is to be recited." -- Mv.X.5.14
"When the Community, without having adjudicated the matter, without having gotten to the roots for a dispute in the Community ... a schism in the Community, a split in the Community, a falling apart in the Community, a separation in the Community -- performs a Community unification, that is a non-Dhamma Community-unification.
"When the Community, having adjudicated the matter, having gotten to the roots for a dispute in the Community ... a schism in the Community, a split in the Community, a falling apart in the Community, a separation in the Community -- performs a Community unification, that is a Dhamma Community-unification." -- Mv.X.6.1