Being anxious to save as many men as possible from misguidance and damnation, the Holy Prophet ﷺ took great pains to convince the deniers, and was specially lenient and gentle with the People of the Book. In this verse, Allah informs him that their denial is not due to lack of convincing arguments and proofs, but is motivated by pride and self-satisfaction, for each of the two groups -- namely, the Jews and the Christians -- believes its own religion to be the only genuine religion, and there is no likelihood of pleasing either of them until and unless the Holy Prophet ﷺ accepts their religion. The religions of the Jews and the Christians, no doubt, were once genuine and had been instituted by Allah. But each had since distorted its religion out of shape; moreover, in sending down Islam as the final Shari'ah, Allah had abrogated all the earlier ones, and hence Islam had by now become the only Shari'ah acceptable to Allah, and in this sense the only genuine and veritable "guidance" possible in this last of all the ages.
It is on account of the present distorted state of the earlier religions, and specially because of their having been abrogated by Divine Commandment that Verse 120 equates them with Ahwa' (the plural of Hawa) -- that is to say, personal desires, or individual opinions and baseless conjectures. Since the deniers are not willing to extricate themselves from their desires and fancies, it is not possible to please them without accepting their opinions -- a thing which a Messenger of Allah can never do. Should they affect a more friendly stance towards the Holy Prophet g , Allah asks him to say to them in plain and simple words that the only guidance worth the name is that which comes from Allah -- and He has already made it clear enough that Islam is now the only form of "guidance" acceptable to Him.
Now, supposing just for the sake of supposing that he should accept their fancies in spite of having received the Truth from Allah through revelation, the verse informs him that in such a case he would find no helper to save him from divine wrath. Other verses of the Holy Qur'an, of course, definitely establish the fact that Allah is pleased and will always remain pleased with the Holy Prophet ﷺ ، and thus he can never be the object of divine wrath. Since divine wrath necessarily follows upon the acceptance of baseless fancies, it is logically impossible for him to follow the opinions of the Jews and the Christians, as divine pleasure and divine wrath cannot be combined with each other. On the other hand, they can never be pleased with him unless he follows their wishes. Consequently, one cannot expect from them any change of heart. Hence, the purport of Verse 120 is to advise the Holy Prophet not to worry too much about them.32
32. Let us add that the warning is apparently addressed to the Holy Prophet ﷺ ، but is really intended for deniers, the purpose being to make them realize the dire consequences of their vanity. In fact, divine wrath is already visible, for the warning has been administered to them, not directly but obliquely, which shows the contempt in which Allah holds them -- Translator ]