Surah 3. Aal-Imran, Ayah 19

Most of the classical commentators are of the opinion that the people referred to are the followers of the Bible, or of parts of it - i.e., the Jews and the Christians. It is, however, highly probable that this passage bears a wider import and relates to all communities which base their views on a revealed scripture, extant in a partially corrupted form, with parts of it entirely lost.

I.e., all these communities at first subscribed to the doctrine of God's oneness and held that man's self-surrender to Him (islam in its original connotation) is the essence of all true religion. Their subsequent divergencies were an outcome of sectarian pride and mutual exclusiveness.

 i.e., full submission to the Will of Allah.

 No community split into believers and disbelievers until they received the knowledge given by their prophet.

Bagyan: through envy, through selfish contumacy or obstinacy, through sheer contrary-mindedness, or desire to resist or rebel. Cf. ii. 90, and ii. 213.