ʿUmar asking rain through the Prophet's uncle
He would not use the Prophet's name after his death, and asked al-ʿAbbās to pray instead.
اللَّهُمَّ إِنَّا كُنَّا نَتَوَسَّلُ إِلَيْكَ بِنَبِيِّنَا فَتَسْقِينَا
O Allah, we used to ask You through our Prophet and You gave us rain. Now we ask You through the uncle of our Prophet, so give us rain. And they were given rain.
The full narration
Narrated Anas:Whenever drought threatened them, `Umar bin Al-Khattab, used to ask Al-Abbas bin `Abdul Muttalib to invoke Allah for rain. He used to say, "O Allah! We used to ask our Prophet to invoke You for rain, and You would bless us with rain, and now we ask his uncle to invoke You for rain. O Allah ! Bless us with rain."(1) And so it would rain
Source
Ṣaḥīḥ al-Bukhārī · 1010
Ṣaḥīḥ
- Agreed upon as authentic (al-Bukhārī / Muslim)