Musnad Ahmad 26:57

Jarir narrated to us, from Mansur, from Abu Wa'il, from Abdullah, who said: Some people said: "O Messenger of Allah, shall we be held accountable for our deeds during the Jahiliyyah (pre-Islamic period)?" He said: "Whoever among you does good in Islam, he shall not be held accountable for it. And whoever does evil, he shall be held accountable for his first and last deeds."