See you not that Allah merges the night into the day, and merges the day into the night, and has subjected the sun and the moon, each running its course for a term appointed; and that Allah is All-Aware of what you do (29)That is because Allah, He is the Truth, and that which they invoke besides Him is falsehood; and that Allah, He is the Most High, the Most Great (30)

The Might and Power of Allah

Allah tells us that He

يُولِجُ اللَّيْلَ فِي النَّهَارِ

(merges the night into the day,) meaning, He takes from the night and adds to the day, so that the day becomes longer and the night shorter, which is what happens in summer when the days are longest; then the day starts to become shorter and the night longer, which is what happens in winter.

وَسَخَّرَ الشَّمْسَ وَالْقَمَرَ كُلٌّ يَجْرِي إِلَىٰ أَجَلٍ مُسَمًّى

(and has subjected the sun and the moon, each running its course for a term appointed;) It was said that this means, each runs within its set limits, or it means until the Day of Resurrection; both meanings are correct. The first view is supported by the Hadith of Abu Dharr, may Allah be pleased with him, in the Two Sahihs, according to which the Messenger of Allah ﷺ said:

يَا أَبَا ذَرٍّ! أَتَدْرِي أَيْنَ تَذْهَبُ هَذِهِ الشَّمْسُ؟

(O Abu Dharr! Do you know where this sun goes) I (Abu Dharr) said: "Allah and His Messenger know best." He said:

فَإِنَّهَا تَذْهَبُ فَتَسْجُدُ تَحْتَ الْعَرْشِ، ثُمَّ تَسْتَأْذِنُ رَبَّهَا فَيُوشِكُ أَنْ يُقَالَ لَهَا: ارْجِعِي مِنْ حَيْثُ جِئْتِ

(It goes and prostrates beneath the Throne, then it seeks permission from its Lord, and soon it will be said: "Go back from whence you came.") Ibn Abi Hatim recorded that Ibn 'Abbas said, "The sun is like flowing water, running in its course in the sky during the day. When it sets, it travels in its course beneath the earth until it rises in the east." He said, "The same is true in the case of the moon." Its chain of narration is Sahih.

 وَأَنَّ اللَّهَ بِمَا تَعْمَلُونَ خَبِيرٌ

(and that Allah is All-Aware of what you do.) This is like the Ayah,

أَلَمْ تَعْلَمْ أَنَّ اللَّهَ يَعْلَمُ مَا فِي السَّمَاءِ وَالْأَرْضِ ۗ

(Know you not that Allah knows all that is in the heaven and the earth?)(22:70). The meaning is that Allah is the Creator Who knows all things, as He says:

اللَّهُ الَّذِي خَلَقَ سَبْعَ سَمَاوَاتٍ وَمِنَ الْأَرْضِ مِثْلَهُنَّ

(It is Allah Who has created seven heavens and of the earth the like thereof)(65:12).

ذَٰلِكَ بِأَنَّ اللَّهَ هُوَ الْحَقُّ وَأَنَّ مَا يَدْعُونَ مِنْ دُونِهِ الْبَاطِلُ 

(That is because Allah, He is the Truth, and that which they invoke besides Him is falsehood;) means, He shows you His Signs so that you may know from them that He is the Truth, i.e., He truly exists and is truly divine, and that all else besides Him is falsehood. He has no need of anything else, but everything else is dependent on Him, because everything in heaven and on earth is created by Him and is enslaved by Him; none of them could move even an atom's weight except with His permission. If all the people of heaven and earth were to come together to create a fly, they would not be able to do so. Allah says:

ذَٰلِكَ بِأَنَّ اللَّهَ هُوَ الْحَقُّ وَأَنَّ مَا يَدْعُونَ مِنْ دُونِهِ الْبَاطِلُ وَأَنَّ اللَّهَ هُوَ الْعَلِيُّ الْكَبِيرُ

(That is because Allah, He is the Truth, and that which they invoke besides Him is falsehood; and that Allah, He is the Most High, the Most Great.) meaning, He is the Most High and there is none higher than Him, and He is the Most Great Who is greater than everything. Everything is subjugated and insignificant in comparison to Him.