Musnad Ahmad 2:109

Waki’ narrated to us, Sufyan narrated to us, from Abu Ya’fur al-‘Abdi, who said: I heard an old man in Makkah during the governorship of al-Hajjaj narrating from ‘Umar ibn al-Khattab, that the Prophet, peace and blessings of Allah be upon him, said to him: "O ‘Umar, you are a strong man, so do not crowd at the Stone (al-Hajar) and harm the weak. If you find a space, then touch it; otherwise, face it, then proclaim the oneness of Allah (tahlil) and proclaim the greatness of Allah (takbir)."