Suuratul An-Nisaa’ Verse 1.
يَـٰٓأَيُّهَا ٱلنَّاسُ ٱتَّقُوا۟ رَبَّكُمُ ٱلَّذِى خَلَقَكُم مِّن نَّفْسٍ وَٰحِدَةٍ وَخَلَقَ مِنْهَا زَوْجَهَا وَبَثَّ مِنْهُمَا رِجَالًا كَثِيرًا وَنِسَآءً ۚ
وَٱتَّقُوا۟ ٱللَّـهَ ٱلَّذِى تَسَآءَلُونَ بِهِۦ وَٱلْأَرْحَامَ ۚ إِنَّ ٱللَّـهَ كَانَ عَلَيْكُمْ رَقِيبًا ﴿١
1. O mankind! Be dutiful to your Lord, Who created you from a single person (Adam), and from him He created his wife [Hawwa (Eve)], and from them both He created many men and women and fear Allah through Whom you demand your mutual (rights), and (do not cut the relations of) the wombs (kinship) . Surely, Allah is Ever an All-Watcher over you.
Tafsir Ibn Kathir Volume 2, Page 370.
﴿إِنَّ اللَّهَ كَانَ عَلَيْكُمْ رَقِيباً﴾
“Surely, Allah is always watching over you” means, He watches all your deeds and sees your every circumstance. In another Ayah (58:6), Allah said;
﴿وَاللَّهُ عَلَى كُلِّ شَىْءٍ شَهِيدٌ﴾
“And Allah is Witness over all things”
An authentic Hadith states,
«اعْبُدِاللهَ كَأَنَّكَ تَرَاهُ، فَإِنْ لَمْ تَكُنْ تَرَاهُ،فَإِنَّهُ يَرَاك»
“Worship Allah as if you see Him, for even though you cannot see Him, He sees you.”
This part of the Ayah encourages having a sense of certainty that Allah is always watching, in a complete and perfect manner. Allah mentioned that He has created mankind from a single father and a single mother, so that they feel compassion for each other and are kind to the weaker among them.