That is, books. Each people followed an invented book other than the Book of Allah, and thus they became divided and at variance. For those who embrace division and disagreement do not follow the pure monotheistic way, which is pure Islam—namely, devoting religion sincerely to Allah—as Allah mentioned in His words:

“They were commanded only to worship Allah, devoting religion sincerely to Him as people of pure faith, to establish prayer, and to give zakat. That is the upright religion.”

[Surah al-Bayyina: 5]

In another verse, He said:

“So set your face firmly toward the religion in pure faith—the natural disposition of Allah upon which He created humanity. There is no altering Allah’s creation. That is the upright religion, but most people do not know. Turn to Him in repentance, fear Him, establish prayer, and do not be among the polytheists—among those who divided their religion and became factions, each party rejoicing in what it possessed.”

[Surah al-Rūm: 30–32]

Thus, He forbade him to be among the polytheists who divided their religion and became factions. He repeated the word “among” to show that the second phrase is a grammatical substitute for the first. The substitute is what the statement is intended to designate, while what precedes it merely prepares the way for it.

Allah Most High also said:

“We certainly gave Moses the Book, but disagreement arose concerning it. Had it not been for a prior decree from your Lord, judgment would already have been passed between them.”

[Surah Hūd: 110]

Up to His words:

“Had your Lord willed, He would have made humanity one community, but they will continue to differ—except those upon whom your Lord has mercy; and for that He created them.”

[Surah Hūd: 18–119]

He thus stated that those who receive mercy do not differ.

It has been mentioned in more than one place that the religion of all the prophets is Islam. Thus, Allah Most High said concerning Noah:

“I have been commanded to be among the Muslims.”

[Surah al-Naml: 91]

And He said concerning Abraham: