Musannaf Ibn Abi Shayba 17:1165

'Abdah narrated to us, from Yahya bin Sa'id, from Sa'id bin al-Musayyib, who said: Ibrahim was the first of the people to host a guest, and the first of the people to trim his mustache, and clip his nails, and shave his pubic hair, and the first of the people to be circumcised. And he was the first of the people to see gray hair, so he said: "O Lord, what is this?" He said: "Dignity." He said: "O Lord, increase me in dignity."