Musnad Ahmad 26:248

Hujayn ibn al-Muthanna narrated to us, Isra'il narrated to us, from Abu Ishaq, from Abu 'Ubaydah, from 'Abdullah, that he was in the mosque supplicating. The Prophet, peace and blessings of Allah be upon him, entered while he was supplicating, and he said: "Ask, and you shall be given." And he was saying: "O Allah, I ask You for faith that does not turn back, and bliss that does not run out, and the companionship of the Prophet, peace and blessings of Allah be upon him, in the highest chambers of Paradise, the Garden of Eternity."