Musnad Ahmad 35:9

'Uthman ibn 'Umar narrated to us, Yunus informed us, from al-Zuhri, from 'Urwah, that Hakim ibn Hizam informed him, saying: I said, "O Messenger of Allah, have you considered matters I used to perform as acts of worship (*tahannuth*) during the Pre-Islamic period (Jahiliyyah)?" He said, "You have accepted Islam along with your previous deeds." And *al-tahannuth* means: worship.