Musnad Ahmad 1018:87

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Abu Bishr, from Salam ibn ‘Amr, from a man among the companions of the Prophet, may God bless him and grant him peace, that the Prophet, may God bless him and grant him peace, said: "Your brothers, treat them well—or do good to them—and seek their help with what overcomes you, and help them with what overcomes them."