In this video:
Dr Zakir Naik says that in the quran it says that:
We did indeed offer the Trust to the Heavens and the Earth and the Mountains; but they refused to undertake it, being afraid thereof: but man undertook it;- He was indeed unjust and foolish;-
However, Dr Zakir Naik then goes on to say that this question (that all humans were asked) was washed off from our memories, so we can perform the worldly test properly.
Dr Zakir Naik does not make it clear where it says that all human memory of this question has been washed off. Anyone know where it says that once Allah asked all humans this question, their memory was washed off?