Musnad Ahmad 929:1

Sufyan narrated to us, from ‘Asim, from Abu ‘Uthman, from my father, who said: I had a cousin whose house was far away. I said: "If only you would acquire a donkey or something [to ride]." He said: "It would not please me if my house were pegged [next] to the house of Muhammad, may Allah bless him and grant him peace." He said: I did not hear a word from him that was more hateful to me than that. He said: Then he mentioned the footsteps to the mosque, so he asked the Prophet, may Allah bless him and grant him peace, and he said: "Indeed, for him, with every step, is a degree."