And if your Lord had willed, He would have made mankind one nation. This means He would have compelled them to be of one nation, that is, one religion, which is the religion of Islam, as His saying goes: 'Indeed, this is your nation, one nation.' This statement includes the negation of compulsion, and that He did not compel them to agree on the religion of truth. Rather, He enabled them to choose, which is the basis of accountability. Some chose the truth and some chose falsehood, so they differed. Therefore, He said: 'And they will continue to differ, except for whom your Lord has mercy upon.' This refers to those whom Allah has guided and shown kindness, so they agreed on the religion of truth without differing in it. And for this reason, He created them. This refers to what was indicated in the first statement and what it contained, meaning: and for this reason, from the enabling and choice that led to the disagreement, He created them, to reward the one who chooses the truth for his good choice, and to punish the one who chooses falsehood for his bad choice. And the word of your Lord was fulfilled, which is His saying to the angels: 'I will surely fill Hell with jinn and mankind all together,' due to His knowledge of the multitude who choose falsehood.