Majma al-Zawaid — Hadith 2847

Sayyiduna Abd al-Rahman bin Abza reports from his father about the Prophet (peace and blessings be upon him) that when he supplicated during the prayer, he would place his hand on his thigh and point with his finger like this. He kept his little finger lowered, and he also kept the finger next to it lowered.
Imam al-Tabarani recorded it in al-Mu'jam al-Kabir, also through the narrator named Rashid.