Musannaf Ibn Abi Shayba 35:95

'Abd al-A'la narrated to us, from Khalid, from 'Ikrimah, from Ibn 'Abbas, that a questioner asked the Prophet (may Allah bless him and grant him peace): "I threw [the pebbles] after I had entered the evening." He said: "There is no harm." He said: And he said: "I shaved before I slaughtered." He said: "There is no harm."