Musnad Ahmad 830:74

Rawh narrated to us, Uthman al-Shahham narrated to us, Muslim ibn Abi Bakrah narrated to me, that he passed by his father while he was supplicating and saying: "O Allah, I seek refuge in You from disbelief, poverty, and the punishment of the grave." He said: So I took them from him, and I used to supplicate with them at the end of every prayer. He said: So he passed by me while I was supplicating with them, and he said: "O my son, where did you grasp these words?" He said: O my father, I heard you supplicating with them at the end of every prayer, so I took them from you. He said: "Then adhere to them, O my son, for the Messenger of Allah, may Allah bless him and grant him peace, used to supplicate with them at the end of every prayer."