Musannaf Ibn Abi Shayba 3:1624

Al-Thaqafi narrated to us, from Khalid, from Abu Qilabah, who said: Malik ibn al-Huwayrith used to come to us. He would say: "Shall I not narrate to you about the prayer of the Messenger of Allah, may Allah bless him and grant him peace?" Then he would pray at a time other than the time of prayer. When he raised his head from the second prostration in the first rak'ah, he would sit straight, then he would stand up and support himself [on the ground].