Musnad Ahmad 8:183

Hujayn ibn al-Muthanna and Abu Sa’id narrated to us, they said: Isra’il narrated to us, from Abu Ishaq. Abu Sa’id said: He said: Abu Ishaq narrated to us, from Mus’ab ibn Sa’d ibn Abi Waqqas, from his father: That he swore by al-Lat and al-‘Uzza. His companions said to him: "You have spoken nonsense." So he came to the Prophet, peace and blessings of Allah be upon him, and said: "My covenant (with Islam) was recent, and I swore by al-Lat and al-‘Uzza." The Prophet, peace and blessings of Allah be upon him, said to him: "Say: 'There is no god but Allah alone' three times, and spit to your left three times, and seek refuge in Allah from the Shaytan, and do not do it again."