Musnad Ahmad 1018:52

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, he said: I heard ‘Abd al-Hamid, the companion of al-Ziyadi, narrating from ‘Abdullah ibn al-Harith, narrating from a man among the companions of the Prophet, may Allah bless him and grant him peace, that he entered upon the Prophet, may Allah bless him and grant him peace, while he was eating the pre-dawn meal (suhur). He said: "It is a blessing that Allah has given to you, so do not abandon it."