Musnad Ahmad 30:2672

Yazid narrated to us, he said: Muhammad ibn ‘Amr informed us, from al-Zuhri, from Humayd ibn ‘Abd al-Rahman, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "For every people of a deed, there is a gate from the gates of Paradise; they are called from it by that deed. And for the people of fasting, there is a gate they are called from, which is called al-Rayyan." Abu Bakr said: "O Messenger of Allah, will anyone be called from all of those gates?" He said: "Yes, and I hope that you will be among them, O Abu Bakr."