– Surely the religion with God is Islam

Several verses in this sūra make exclusive claims for Islam. This verse declares that Allah’s religion (dīn) is Islam. Further claims for Islam come at verses 67 and 85 (see also v. 110). In Arabic, islām simply means “submission” or “surrender,” so the Quran does not necessarily have the religion in mind every time it uses this word (see v. 20). Islām by itself also does not necessarily mean “surrender to Allah,” because the very same word is used for political surrender or submission.

3.19 – Those who were given the Book did not differ

The Quran contains a number of statements that the People of the Book differed (ikhtalafa). The “knowledge” in the verse is not explained, but Muslim commentators have tended to identify this knowledge with the recitations of the messenger. See the comments on this theme at 98.4.