Musannaf Ibn Abi Shayba 21:628

Ya'la ibn 'Ubayd narrated to us, he said: Hajjaj ibn Dinar narrated to us, from Mansur, from Mujahid, from Ibn 'Abbas, that he disliked pointing at the crescent moon, but rather he would turn towards it and say: "Allah is the Greatest. Praise be to Allah who caused such-and-such crescent to pass and brought such-and-such crescent."