in a report traced back to the Prophet: “Best in deeds” means the soundest in intellect, the most scrupulous in avoiding Allah’s prohibitions, and the swiftest in obeying Allah. 170/A
Al-Fudayl ibn Iyad said: “Best in deeds” means the most sincere and the most correct. He said: A deed is not accepted until it is both sincere and correct. Sincere means that it is done for Allah, and correct means that it accords with the sunnah.
Al-Hasan said: It means which of you is most detached from this world and most forsaking of it.
Al-Farra said: The verb denoting testing does not directly govern “which,” except with an implied expression intervening between them (1), as when one says, “I tested you in order to see which of you is more obedient.” Similarly: “Ask them which of them will guarantee that” (al-Qalam 40)—that is, ask them and consider which of them. Thus, “which” is in the nominative position as the subject, and “best” is its predicate. “And He is the Almighty,” in His punishment of those who disobey Him, “the All-Forgiving,” to those who repent to Him.
“He who created seven heavens in layers. You will never see any imperfection in the creation of the Most Merciful. So look again: do you see any flaw? Then look again and again: your sight will return to you humbled and exhausted.”
“He who created seven heavens in layers”: one layer above another, with some of them above others. “You will never see any imperfection in the creation of the Most Merciful.” Hamzah and al-Kisa’i recited it as tafawwut, with a doubled waw and without an alif, while the others recited it with a single waw preceded by an alif. Both are linguistic forms, like tahammul and tahamul, and tatahhur and tatahur. Its meaning is: O son of Adam, you will see no crookedness, disparity, or contradiction in the creation of the Most Merciful; rather, it is straight and harmonious. It derives from fawt (3), which is for some parts to be out of alignment with others due to their lack of uniformity. “So look again”: repeat your gaze; that is, look, then look again. “Do you see any flaw?”—any cracks or fissures.
“Then look again and again.” Ibn Abbas said: Time after time. “Your sight will return”: it will turn back and return to you, “humbled”—abased, humiliated, and driven away, having not seen what it sought—“and exhausted”: weary and spent, having failed to attain what it sought.
It is related from Ka‘b that he said: The lowest heaven is a restrained wave; the second is white marble; the third is iron; the fourth is yellow (4)—that is, copper; the fifth is silver; the sixth is gold; and the seventh is a red ruby. Between the seventh heaven and the seven veils are deserts of light (6).