The Prophet (ﷺ) said, "I am your predecessor at the Lake-Fount, and some of you will be brought in front of me till I will see them and then they will be taken away from me and I will say, 'O Lord, my companions!' It will be said, 'You do not know what they did after you had left.'
Sahih al-Bukhari Book 81, Hadith 164