It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that Wahb bin Umayr took part in Uhud as a disbeliever. He was wounded and came to be counted among the slain. A man from the Ansar passed by him, recognised him and thrust his sword into his belly until it came out of his back, then left him. When night fell and the cold reached him, he made his way to Makkah and recovered. Then he and Safwan bin Umayyah sat together in the Hijr, and Wahb said: "Were it not for my dependants and a debt upon me, I would love to be the one who kills Muhammad." Safwan said to him: "Then how would you do it?" He said: "I am a swift man; no one can catch me. I will go to him, take him off guard, then strike him with the sword and join the horses, and no one will be able to catch me." Safwan said to him: "Your dependants will be with my dependants, and your debt is upon me." So he went out, had his sword sharpened and poisoned, and then set out for Madinah, intending nothing but to kill the Prophet (peace and blessings be upon him). When he reached Madinah, Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) saw him, and he found this disturbing and distressing. So he said to the Companions of the Prophet (peace and blessings be upon him): "I have seen Wahb, and his arrival has made me suspicious. He is a treacherous man; surround your Prophet (peace and blessings be upon him)." So the Muslims gathered around the Prophet (peace and blessings be upon him). Then Wahb came, stood before the Prophet (peace and blessings be upon him) and said: "Good morning to you, O Muhammad." He (peace and blessings be upon him) said: "Allah has given us something better than it in its place." He said: "I remember that you used to speak of this old greeting with pride." The Prophet (peace and blessings be upon him) said to him: "What has brought you here?" He said: "I have come to ransom your captives." He (peace and blessings be upon him) said: "What about the sword?" He said: "We carried it on the day of Badr, but we neither succeeded nor prospered." He (peace and blessings be upon him) said: "What was it you said to Safwan in the Hijr: 'Were it not for my dependants and a debt upon me, I would kill Muhammad myself with my own hands'?" The Prophet (peace and blessings be upon him) told him his whole story, and Wahb said: "Hah, what did you say?" He (peace and blessings be upon him) told him again. Wahb said: "You used to tell us the news of the earth and we would deny you, but now I see you telling the news of the heavens. I bear witness that there is no true deity except Allah and that you are the Messenger of Allah." Then he said: "O Messenger of Allah, give me your turban." The Prophet (peace and blessings be upon him) gave him his turban, and then he set out for Makkah. Sayyiduna Umar (may Allah be pleased with him) said: "When he came to Madinah he was more hateful to me than a pig, and when he returned (having embraced Islam) he was dearer to me than some of my own children."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14192