Musnad Ahmad 2:240

Yahya ibn Hammad and ‘Affan narrated to us, they said: Abu ‘Awanah narrated to us, from Dawud ibn ‘Abdullah al-Awdi, from Humayd ibn ‘Abd al-Rahman al-Himyari: Ibn ‘Abbas narrated to us in Basra, he said: I was the first to come to ‘Umar when he was stabbed. He said: "Memorize three things from me, for I fear that the people will not reach me [in time]: As for me, I have not issued a judgment regarding the *kalalah* (one who leaves behind neither parents nor children), I have not appointed a successor over the people, and every slave of mine is free." The people said to him: "Appoint a successor." He said: "Whichever of these I do, one who is better than me has done it. If I leave the affair of the people to them, the Prophet of Allah, peace and blessings be upon him, left it. And if I appoint a successor, one who is better than me appointed a successor: Abu Bakr." I said to him: "Receive glad tidings of Paradise. You accompanied the Messenger of Allah, peace and blessings be upon him, and you prolonged your companionship with him, and you took charge of the affair of the believers, so you were strong and you fulfilled the trust." He said: "As for your giving me glad tidings of Paradise, by Allah, if I had—‘Affan said: 'Nay, by Allah, besides whom there is no god, if I had'—the world and all that is in it, I would ransom myself with it from the terror of what is before me before I know the news. As for your statement regarding the affair of the believers, by Allah, I wish that it were *kafan* (a wash/break-even), neither for me nor against me. And as for what you mentioned of the companionship of the Prophet of Allah, peace and blessings be upon him, that is [as you said]."