Sahih al-Bukhari 6189

Abdullah ibn Muhammad narrated to us: Sufyan narrated to us, who said: I heard Ibn al-Munkadir say: I heard Jabir ibn Abdullah, may Allah be pleased with them both, say: A boy was born to one of us, and he named him al-Qasim. They said, ‘We will not give you the kunya Abu al-Qasim, nor grant you that distinction.’ He came to the Prophet, peace and blessings be upon him, and told him. He said, ‘Name your son Abd al-Rahman.’