His words, Exalted is He:

By the day when it reveals her [the sun],

He said:

This means: the light of faith removes the darkness of ignorance and extinguishes the flames of the Fire.

and by the night when it enshrouds her,

He said:

This means: sins, and persistence in committing them, conceal the light of faith so that it does not shine within the heart, and does not manifest its effect in his qualitites (ṣifāt), just as the Prophet ﷺ said, ‘Desire (hawā) and lust (shahwa) overwhelm knowledge (ʿilm), intellect (ʿaql) and lucidity (bayān).’^{1This tradition also appears in the context of 38:26 and under 2:106, and is listed in Iṣfahānī, Ḥilyat al-awliyāʾ (vol. 10, p. 88) not as a Prophetic ḥadīth, but a saying of al-Ḥārith b. Asad.} [This is due] to the pre-eternal decree of God, Mighty and Majestic is He.^{2That is, reading li-sābiq al-qadar in MSS Z515, f. 134b and F3488, f. 317b, or li-sābiqat al-qadar in F638, f. 66b, as opposed to li-sābiq al-qudra in the printed edition.}

His words, Exalted is He:

successful indeed will be the one who purifies it,^{1It being a reference back to the soul, which was mentioned in verse 7: By the soul and the One who proportioned it.}

He said:

He who is granted [the ability to consider] (naẓar) the matter of his final return (maʿād), succeeds.

and he will indeed have failed who eclipses it.

He said:

The soul which is misled by God, Mighty and Majestic is He, such that it does not give the matter of its final return any consideration, will fail.