Musannaf Ibn Abi Shaybah 8558 — Those who used to perform the prayer

Ishaq bin Abdullah bin Kinanah said: One of the governors sent me to Sayyiduna Ibn Abbas (may Allah be pleased with them both) to ask him about the prayer for rain (istisqa'). Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: "Why did he not ask me about it himself?" Then he said: "The Prophet (peace and blessings be upon him) came out with humility, without adornment, with humbleness and earnest entreaty, walking slowly, and he prayed two rak'ahs just as he used to lead the Eid prayer, but he did not give a sermon like this sermon of yours."