Musnad Ahmad Hadith 22000

Hisan bin Kahil, may Allah have mercy on him, says that once I joined the gathering of Abdur Rahman bin Samurah, may Allah have mercy on him, whose hair and beard had turned white. He said that Mu'adh bin Jabal, may Allah be pleased with him, narrated to me from the Prophet Muhammad, peace and blessings be upon him, that whoever dies in such a state that he bears witness that there is no god but Allah and that I am the Messenger of Allah, and this testimony is with certainty in his heart, then all his sins will be forgiven. I asked him, "Did you really hear this hadith from Mu'adh, may Allah be pleased with him?" People began to reproach me for this, but he said, "Do not reproach or scold him, leave him alone. I did indeed hear this hadith from Mu'adh, may Allah be pleased with him, who narrated it from the Prophet Muhammad, peace and blessings be upon him." Later, I asked people, "Who is he?" and they told me who he was.