AHMAD-ZUHD 1693:
from Man al-Khulafāʾ —
[Machine] Abu Bakr and Umar, I said, we already know them. So who is Umar? He said, if you live, you will find out, and if you die, he will come after you.
الزهد لأحمد ١٦٩٣:
عن من الخلفاء —
أَبُو بَكْرٍ وَعُمَرُ وَعُمَرُ قُلْتُ أَبُو بَكْرٍ وَعُمَرُ قَدْ عَرَفْنَاهُمَا فَمَنْ عُمَرُ؟ قَالَ إِنْ عِشْتَ أَدْرَكْتَ وَإِنْ مُتَّ كَانَ بَعْدَكَ