Musnad Ahmad 132:39

Ishaq ibn Isa narrated to us, Ibn Lahi'ah narrated to us, from Khayr ibn Nu'aym al-Hadrami, from Sahl ibn Mu'adh ibn Anas al-Juhani, from his father, who said: The Messenger of Allah, may Allah bless him and grant him peace, said: "The remembrance of Allah (dhikr) is superior to spending in the way of Allah, Blessed and Exalted is He, by seven hundred thousand times."