Musannaf Ibn Abi Shayba 33:865

Husayn ibn Ali narrated to us, from Ubayd ibn Abd al-Malik, who said: Someone who saw Umar ibn Abd al-Aziz standing at Arafah informed me that he was supplicating and saying with his finger like this—meaning he was gesturing with it—"O Allah, increase the doers of good among the nation of Muhammad in goodness, and return their evildoers to repentance." Then he would say like this, and he would rotate his finger, "O Allah, and encompass those behind them with Your mercy."