Salim, the freed slave of Abu Hudhayfah (may Allah be pleased with him) narrates: He was with Sayyiduna Abu Bakr (may Allah be pleased with him) on a roof during Ramadan while he (Abu Bakr) was praying. He came to him and said: O Khalifah of the Messenger of Allah, will you not eat? He gestured with his hand, until he had done so twice. Then when it was the third time, he said: "Bring me your food." So he ate and prayed two rak'ahs, then he entered the mosque, and the iqamah for the prayer was called.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6348