Narrater: (Abu Bakra) Hadidth No: (822)

The Prophet said thrice, ''Should I inform you out the greatest of the great sins?'' They said, ''Yes, O Allah's Apostle!'' He said, ''To join others in worship with Allah and to be undutiful to one's parents.'' The Prophet then sat up after he had been reclining (on a pillow) and said, ''And I warn you against giving a false witness, and he kept on saying that warning till we thought he would not stop. (See Hadith No. 7, Vol. 8)