Surah Al Mujadila Tafseer

يَوْمَ يَبْعَثُهُمُ اللَّهُ جَمِيعًا

On the Day when Allah will resurrect them all together,

referring to the Day of Resurrection when He will gather the early and the latter generations in one area,

..

فَيُنَبِّيُهُم بِمَا عَمِلُوا

and inform them of what they did.

He will tell them all that they did in detail, whether good or evil,

أَحْصَاهُ اللَّهُ وَنَسُوهُ

Allah has kept account of it, while they have forgotten it.

meaning, Allah recorded and kept all these actions, even though they have forgotten what they did,

وَاللَّهُ عَلَى كُلِّ شَيْءٍ شَهِيدٌ

And Allah is Witness over all things.

meaning, nothing escapes His knowledge, and no matter is hidden from Him or escapes His complete observation.

Allah's Knowledge encompasses Creation

Then Allah the Exalted informs of His knowledge encompassing all creation, observing it, hearing their speech and seeing them, wherever they may be and in whatever condition they may be in