It is the tradition of Allah -azwj ...

It is the tradition of Allah -azwj , when we look at the Holy Quran, that Allah -azwj does not Expose a Munafiq (i.e., Driving him away from the Guided and the Guidance) unless and until one acts/utters as per his/her hidden intentions.

Accordingly, Allah -azwj , although in clear Knowledge of their actual commitments, who were under the tree, only Praised those who were sincere in their pledge but without specifically excluding the insincere ones – the exposure of their hypocrisy was left for a later time when their actions would lead them to their separation from the praised worthy believers.

After passing away of Rasool-Allah -saww , the differing of Muslims started and reached to the point where some of those who pledged allegiance under the tree, were fighting against each other, thereby, were responsible for the killings of thousands of Muslims in the battle fields (i.e., Jamal, Siffeen).

Some Sunni Muslims, may, try to justify the differing of the ‘Muslims under the tree’, by quoting a Hadith, in which allegedly Rasool-Allah -saww said: ‘ Difference of opinion among my Ummah (Nation) is a mercy ’, but it is against the Words of Allah -azwj in the Holy Quran where Allah -azwj Says: “And mankind was not but one community (united in religion), but (then) they differed. …” [Yunus 10: 19] and there are many other Verses Forbidding the differing (e.g., 6:159, 3:103).

Surely your Lord will Judge between them on the Day of Judgement with regards to what they were differing in [10:93]. The differing in religion means some of them were on the right path whereas the others were on the wrong path, so Allah -azwj will Decide regarding them on the day of Judgement, to whom to reward and to whom to punish. Hence all differing fractions cannot be praiseworthy and one has to relate oneself to the guided ones and keep away from the strayed.