Musnad Ahmad 1704

Abdur-Rahman bin Abi Bakr narrated that: Ashabus-Suffah were poor people. The Messenger of Allah (ﷺ) said on one occasion: “Whoever has food for two, let him take a third person with him - ‘Affan said: three people, whoever has food for four, let him take a fifth and sixth person with him,” or words to that effect. Abu Bakr came with three people and the Prophet (ﷺ) took ten people with him, and Abu Bakr took three.