Concise Quran Commentary
Allah alternates between the length of the day and night. Indeed, in that alternation is a lesson in the power of Allah and His oneness, for those who have foresight.
يُقَلِّبُ ٱللَّهُ ٱلَّيْلَ وَٱلنَّهَارَ ۚ إِنَّ فِى ذَٰلِكَ لَعِبْرَةً لِّأُو۟لِى ٱلْأَبْصَـٰرِ
Allah alternates the night and day. Indeed, there is a lesson in this for people of insight.