Musnad Ahmad 129:2

Isma'il narrated to us, Ayyub narrated to us, from Abu Qilabah, who said: Abu Sulayman Malik ibn al-Huwayrith came to our mosque and said: "By Allah, I am praying, and I do not intend the prayer [itself], but I intend to show you how I saw the Prophet, may Allah bless him and grant him peace, pray." He said: "So he sat in the first rak'ah when he raised his head from the last prostration, then he stood up."