Musnad Ahmad 189:0

Narrated to us by Yahya ibn Sa’id, from Shu’bah, who said: Narrated to us Qatadah, from Abu al-Maliyah, from Mujashi’ ibn Mas’ud, that he came to the Prophet (ﷺ) with his brother. He said: "I came to the Prophet (ﷺ) with my brother after the conquest, and I said: 'O Messenger of Allah, I have come to you with my brother so that you may take the pledge of allegiance from us for migration.' He (the Prophet) said: 'The migration has passed with its people.' I said: 'Then upon what will you take our pledge?' He said: 'I will take your pledge for Islam, faith, and Jihad.'"