Musnad Ahmad 1018:81

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