Musannaf Ibn Abi Shaybah 4603 — Those who disliked looking aside

Zayd bin Wahb said: Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) saw a man who prayed two rak'ahs after sunset, before the Maghrib prayer, and kept turning around in them. When he had finished the prayer, Sayyiduna Umar struck him with his whip and said: "Do not turn around in prayer." He did not say anything to him about the two rak'ahs.