Have you heard what the Prophet Muhammad (saw) said about the major sins?
 Ubaidullah b. Abu Bakr said:                      I heard Anas b. Malik saying: The Messenger of Allah (may peace be upon him) talked about the major sins, or he was asked about the major sins. Upon this he observed: Associating anyone with Allah, killing of a person, disobedience to parents. He (the Holy Prophet further) said: Should I not inform you about the gravest of the major sins, and (in this connection) observed: False utterance or false testimony. Shu'ba said. It was most probably" false testimony".