Musnad Abu Ya'la al-Mawsili 2:48

Ubayd Allah ibn Umar al-Qawariri narrated to us, Yazid ibn Harun narrated to us, Asim ibn Muhammad ibn Zayd narrated to us, from his father, from Ibn Umar, from Umar, who said—I do not know it except as attributed to the Prophet (may Allah bless him and grant him peace)—he said: Allah, Blessed and Exalted is He, said: "Whoever humbles himself to Me like this"—and Yazid inclined his palm toward the earth—"I will raise him like this"—and Yazid gestured with the palm of his hand toward the sky.