Musnad Ahmad 1153:374

'Abdullah ibn al-Walid narrated to us, Sufyan narrated to us, Mu'awiyah ibn Ishaq narrated to us, from 'A'ishah bint Talhah, from 'A'ishah, the Mother of the Believers, who said: We asked the Prophet, peace and blessings of Allah be upon him, for permission to participate in Jihad. He said: "Your Jihad, or your sufficiency, is the Hajj."