Musnad Ahmad 26:849

Hasan ibn Musa narrated to us, he said: I heard Hudayj, the brother of Zuhayr ibn Mu'awiyah, from Abu Ishaq, from Abdullah ibn Utbah, from Ibn Mas'ud, who said: The Messenger of Allah (peace and blessings of Allah be upon him) sent us to the Negus, and we were about eighty men, among them Abdullah ibn Mas'ud, Ja'far, Abdullah ibn 'Arfatah, Uthman ibn Maz'un, and Abu Musa. They came to the Negus, and the Quraysh had sent Amr ibn al-Aas and Umarah ibn al-Walid with a gift. When they entered upon the Negus, they prostrated to him, then they hurried to his right and his left. Then they said to him: "Some people from our cousins have settled in your land, and they have turned away from us and from our religion." He said: "Where are they?" They said: "They are in your land, so send for them." So he sent for them. Ja'far said: "I am your speaker today, so follow me." He greeted him and did not prostrate. They said to him: "What is the matter with you that you do not prostrate to the King?" He said: "We do not prostrate except to Allah, the Almighty and Majestic." He said: "And what is that?" He said: "Allah, the Almighty and Majestic, sent His Messenger (peace and blessings of Allah be upon him) to us, and He commanded us not to prostrate to anyone except Allah, the Almighty and Majestic, and He commanded us to pray and give zakat." Amr ibn al-Aas said: "They differ with you regarding Jesus, son of Mary." He said: "What do you say about Jesus, son of Mary, and his mother?" They said: "We say as Allah, the Almighty and Majestic, said: He is the Word of Allah and His Spirit, which He cast to the Virgin, the Chaste, whom no human had touched, and who had not been impregnated by a child." He said: Then he picked up a stick from the ground, then said: "O assembly of Abyssinians, priests, and monks, by Allah, they do not add to what we say about him even the weight of this. Welcome to you, and to the one from whom you have come. I bear witness that he is the Messenger of Allah, for he is the one we find in the Gospel, and he is the Messenger whom Jesus, son of Mary, gave glad tidings of. Settle wherever you wish. By Allah, were it not for the kingdom I am in, I would have gone to him until I was the one carrying his sandals and performing his ablution." He ordered the gift of the others to be returned to them. Then Abdullah ibn Mas'ud hastened until he caught up with Badr, and he claimed that the Prophet (peace and blessings of Allah be upon him) asked for forgiveness for him when news of his death reached him.