Tafsir of An-Nahl 16:63

{For He is their patron today}

This is a narration of the past state in which Satan used to make their deeds seem fair to them. Alternatively, it means He is their patron in this world, using "today" as an expression for the time of the worldly life. The meaning of "their patron" is their companion, and what an evil companion!

Or, it may be interpreted as a narration of the future state—the state of their being tormented in the Fire. That is: He is their helper today, and there is no helper for them other than Him, which is a negation of any helper for them in the most emphatic manner.

It is also permissible that the pronoun refers to the polytheists of Quraysh, meaning: He made the deeds of the disbelievers before them seem fair, so he is the patron of those [past ones] and these [present ones], because they are of them. It is also possible that it involves the omission of a genitive, meaning: He is the patron of their likes today.

{And We have not revealed to you the Book, except for you to make clear to them that wherein they have differed, and as guidance and mercy for a people who believe. And Allah has sent down rain from the sky and given life thereby to the earth after its lifelessness. Indeed, in that is a sign for a people who listen.}