Question: Did ‘Umar (rta) use Prophet Mohammed’s uncle ‘Abbas as an interceder (wasilah) to request rain from Allah after Prophet Mohammed (sws) had passed away? 
  
    Answer: Bukhari has reported in his Sahih that once ‘Umar (rta) asked ‘Abbas (rta) to pray to God for rain:

Anas (rta) narrates: whenever there was a drought, ‘Umar (rta) prayed for rain through ‘Abbas Ibn ‘Abdu’l Muttalib (rta). He [‘Umar] would say: ‘Oh My God We used to ask you for rain through our Prophet (sws) and you would send rain, now we ask you for rain through his uncle. Please send showers on us’. Anas (rta) says that they would then they were bestowed with rain. (Bukhari No: 964)

    In what follows is the wording of the prayer of ‘Abbas (rta): 

He said: Oh Lord! No misfortune befalls except because of (our) sins and none is taken but through repentance. My people had turned to me because of my relation to your prophet (sws) so here are our hands spread before you marred with sins and our foreheads (bowing down) in repentance. So bless us with rain. [Fatulbari 964]

    A study of these and other related information about the matter makes it clear that ‘Umar (rta) requested ‘Abbas (rta) to pray to God for rain. He did not use the Prophet (sws) or his uncle as an interceder. The position of ‘Abbas (rta) is analogical to the one of leader in prayer. Others forwarded him because of his position of respect being uncle of the Prophet (sws).