Musannaf Ibn Abi Shayba 3:1996

Hushaym narrated to us, he said: Mughira informed us, from Ziyad ibn al-Husayn, from Ibn Umar, that he used to say in his prostration: "O Allah, to You my blackness (my physical being) has prostrated, and in You my heart has believed. O Allah, grant me knowledge that benefits me, and deeds that elevate me."