Tafsir of Al-Qasas 28:73

{And from His mercy}—that is, due to the mercy of the Exalted in Majesty—{He made the night and the day that you may rest therein}—that is, in the night—{and that you may seek of His bounty}—that is, in the day, by striving through various forms of earning. In the verse, there is what is termed al-laff wa al-nashr (the folding and the spreading), also called al-tafsir (the explanation), as in the words of Ibn Juyush:

A veiled one who makes the companion dispense with his cup, full though it be, and with his pitcher; The action of the wine, its color, and its taste are in his eyes, his cheeks, and his saliva.

The pronoun in "His bounty" refers to Allah, Exalted be He. Abu Hayyan permitted that it could refer to the day, based on metaphorical attribution, though this is contrary to the apparent meaning. The verse contains an indication of the praise for striving in the pursuit of provision. It has been reported that "the earner is the beloved of Allah," and this does not contradict reliance upon Allah (tawakkul), for whatever the servant attains through his striving is a bounty from Allah—Mighty and Majestic is He—and not something incumbent upon Him, glory be to Him.

{And that you may be grateful}—that is, so that you may be grateful for His blessing, the Exalted, He did what He did; or, so that you may recognize His blessing, the Exalted, and be grateful to Him for it.