And they did not become divided until after knowledge had come to them—out of mutual envy among themselves.} (ash-Shura 13-14).

And the Exalted said in Surah al-Baqarah: {And when there came to them a Book from Allah confirming that which was with them—although before they used to pray for victory against those who disbelieved—but when there came to them that which they recognized, they disbelieved in it; so the curse of Allah is upon the disbelievers.} (al-Baqarah 89).

If someone asks: "Does Allah misguide them?"

We say to him: "Yes, the Exalted misguides them as a retribution for their denial, disbelief, and persistence, just as He guides the believers as a reward for their acknowledgment, faith, and steadfastness, according to His saying in Surah Fussilat: {Whoever does righteousness—it is for his soul; and whoever does evil—it is against it. And your Lord is not ever unjust to [His] servants.}" (Fussilat 46).

And if it is said: "What is the evidence for that from His Mighty Book?"

We say: "The evidences are many, including His saying in Surah an-Nahl..."

{And if Allah had willed, He could have made you [of] one religion, but He misguides whom He wills and guides whom He wills.