Hazrat Umar (rta) Writing Letter To The River Nile
The chain of this narration is weak as can be read below: https://islamqa.info/en/answers/178417/is-it-proven-that-umar-may-allah-be-pleased-with-him-wrote-a-letter-to-the-nile-in-egypt-so-that-its-water-would-flow-by-allahs-leave#:~:text=He%20wrote%20to%20him%2C%20saying,of%20the%20people%20of%20Egypt . According to some, there is no harm in reporting historical incidents despite their weak chain: https://islamqa.org/hanafi/hadithanswers/122827/the-letter-of-sayyiduna-umar-radiyallahu-anhu-to-the-river-nile/ One biographer of Umar (rta), Muhammad Hussein Haykal , has denied the fact that such a ritual ever existed and this particular incident never happened. Read pages 672 to 677 below for his commentary of this event in urdu translation of his famous book, “Al Farouq Omar” . https://drive.google.com/file/d/0B9kHqDDK6NaXQWlNZWFHSHk5eG8/view?resourcekey=0-lfuvOkZyQrr7H3OIyDbkyQ