Sunan an-Nasa'i 2640

(It was narrated from 'Abdullah bin 'Abbas that:a man asked the Prophet "The command of ) Hajj has come while my father is an old man and cannot sit firmly in his saddle; if I tie him (to the saddle) I fear that he will die. Can I perform Hajj on his behalf?" He said: "don't you think that if your father owed a debt and you paid it off, that would be good enough?" He said: "Yes." He said: "Then perform Hajj on behalf of your father