It is reported that Khālid b. Ma’dān – Allāh have mercy on him – said:
There is not a person except he has four eyes: two in his head with which he sees the matters of this worldly life, and two in his heart with which he looks to the matters of the hereafter. So if Allāh wants good for his servant, He opens his heart’s eyes, and so he perceives what he has been promised in the unseen world. Thus he is saved from the unseen [punishment] through the unseen [reward for the obedient].
Al-Dhahabī, Siyar A’lām Al-Nubalā` 4: 543