53. A time will come when such people will, on the one hand, come face to face with the infinite life of the Hereafter, and on the other, they will took back at their past worldly life and realize how puny it was as compared to the life ahead. It is then that they will comprehend what folly they have committed by ruining their eternal future for the sake of ephemeral pleasures and benefits in this worldly life.
54. This refers to the unbelievers' rejection that a time will come when everyone will have to stand before God for His judgement.