Volume 2, Book 17, Number 123:
Narrated Anas:
Whenever drought threatened them, ‘Umar bin Al-Khattab, used to ask Al-Abbas bin ‘Abdul Mut –
talib 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.