Sahih Muslim
The Book of Faith (Kitab Al-Iman)
Book Number: 001 / Hadith Number: 147
It is narrated on the authority of Abu Zubair that he heard Jabir b. 'Abdullah saying. I heard the Messenger of Allah (may peace and blessings be upon him) observing this: Between man and polytheism and unbelief is the abandonment of salat.