Musnad Ahmad 691:0

Narrated to us by Hisham ibn al-Qasim, who said: Narrated to us by al-Mas'udi, from 'Amr ibn Murrah, from Salim ibn Abi al-Ja'd, from Khuraym ibn Fatik, who said: The Messenger of Allah (peace be upon him) went out for the dawn prayer, and when he finished, he stood up and said: "False testimony is equated with associating partners with Allah (shirk)." He repeated it three times, then he recited: "So avoid the impurity of idols and avoid false statement, being inclining to Allah, not associating anything with Him."