Musnad Ahmad 675:2

Waki' narrated to us, Ibn Abi Layla narrated to us, from his brother Isa ibn Abd al-Rahman, who said: We entered upon Abdullah ibn Ukaym while he was ill, visiting him. It was said to him: "If only you would hang something [as an amulet]." He said: "Shall I hang something, when the Messenger of Allah (peace and blessings of Allah be upon him) said: 'Whoever hangs something, he is entrusted to it.'"