Tafsir of Ar-Rum 30:23

"And of His signs is your sleep..."

This is an instance of laff (intertwining). Its arrangement is: "And of His signs is your sleep and your seeking of His bounty by night and by day." However, He separated the first two counterparts with the latter two.

This is because they are two times, and the time and what occurs within it are as one thing, with the laff assisting in this unification. It is also permissible that the meaning intended is: your sleep in both times, and your seeking [of bounty] in both of them. The apparent meaning is the first, due to its repetition in the Qur’an. The most sound of meanings is that which the Qur’an indicates, for those who hear it with attentive ears.

"And of His signs is that He shows you the lightning, fearful and hopeful, and sends down rain from the sky, by which He revives the earth after its death. Indeed, in that are signs for a people who use reason."