A lay person cannot commit “Sangha Bedha” as it is only when bhikkhus are concerened, but “Sangha Bedha” is not division among bhikkhus, but the fact of the matter is that today every single Bhikkhu commits schism or “Sangha Bedha” knowingly or unknowingly.
The Buddha condemned schism in strong terms, saying that a person who starts or joins a schism in a Community knowing or suspecting that he is not on the side of the Dhamma and Vinaya, is destined to be boiled for an aeon in hell (AN V.129; Cv.VII.5.3-4). Buddha’s instruction is to look into the matter and to side with the faction on the side of the Dhamma. The Buddha does not advocate superficial unity 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.
When a bhikkhu has learned that a dispute has led to a schism and he wants to get involved, 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’ …
Thus the ability to take sides requires that one be well-informed about the Buddha’s teachings. 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 the root (the mind-states motivating the schism — see Cv.IV.14.3-4), and then resolve which side was right, based on the Dhamma and Vinaya.
There are cases where bhikkhus have started or joined a schism rooted in corrupted intent, knowing or suspecting that their views and actions deviate from the Dhamma-Vinaya. Those who joined the schismatic faction through ignorance should be won over to the Dhamma side by explaining the true Dhamma-Vinaya to them.
Ven. Sāriputta: “How am I to behave with regard to these (schismatic) bhikkhus?”
The Buddha: “In that case, Sāriputta, take your stance in line with the Dhamma.”
Ven. Sāriputta: “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’ …