"The Prophet ordered placing the hands (on the ground)." And he mentioned in it: "From his father."
Jami` at-Tirmidhi Book 2, Hadith 130
← Previous Hadith "The Prophet ordered placing the hands (on the ground) keeping the feet erect. (by resting feet on the toes and making the tips of the toes facing the Qiblah)."

Jami` at-Tirmidhi Book 2, Hadith 129 Next Hadith → "The Salat of Allah's Messenger (was such that) when he bowed, and when he raised his head from bowing, and when he prostrated, and when he raised his head from prostration it (all) was nearly the same."

Jami` at-Tirmidhi Book 2, Hadith 131