Musannaf Ibn Abi Shayba 33:792

Sharīk narrated to us, from Ismāʿīl ibn Abī Khālid, who said: I heard Khaythama saying regarding this verse: "A Day that will make the children gray-haired" (73:17). He said: A caller will call out on the Day of Resurrection, and the contingent of the Fire will be brought out—from every thousand, nine hundred and ninety-nine. From that, the children will turn gray-haired.