Musnad Ahmad 1060:5

Al-Muqri narrated to us, Haywah ibn Shurayh narrated to us, Baqiyyah narrated to us, Buhayr ibn Sa’d narrated to me, from Khalid ibn Ma’dan, Abu Ruhm al-Sam’i narrated to us, that Abu Ayyub narrated to him, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever comes worshipping Allah, not associating anything with Him, establishing the prayer, giving the zakat, fasting Ramadan, and avoiding the major sins, then for him is Paradise." They asked him: "What are the major sins?" He said: "Associating partners with Allah, killing a Muslim soul, and fleeing on the day of the advance."