This world is the abode of duty and the farm of the Hereafter. It is a place of trade and earning whereas the Hereafter is the abode of reward and punishment, of bounty and damnation.
That is, the reason that the believer is afflicted in this world with tribulation is that God Almighty has made it neither the place of His reward for the believer nor the place of chastisement for the infidel.