2/213 — Why there is disagreement
"People were one community; God sent prophets as bringers of good news and as warners, and with them He sent down the Book with the truth, to judge between people in what they differed about. And those to whom the Book was given differed about it, after the clear proofs had come to them, out of envy between them."
1. Unity — kāna'l-nāsu ummatan wāḥida 2. Prophets and a book — to settle the disagreement 3. Disagreement — and this time among those who received the book
The cause of the division, that is, is not given as ignorance. The text says it plainly: min baʿdi mā jāʾathumu'l-bayyināt — after the clear proofs had come.
بَغْيًۢا بَيْنَهُمْ — root ب-غ-ي: to pass the bound, to begrudge. The cause is given not as a lack of knowledge but as a state held against one another.
This is in the same line as the narrative of the Children of Israel in the earlier sections of the sūra: there too a problem of conduct in spite of knowledge was treated (2/75, 2/89, 2/146). The sūra takes disagreement out of being a matter of knowledge and makes it a matter of character.