Chapter: False witness

The Prophet (ﷺ) was asked about the great sins He said, "They are:-- (1 ) To join others in worship with Allah, (2) To be undutiful to one's parents. (3) To kill a person (which Allah has forbidden to kill) (i.e. to commit the crime of murdering). (4) And to give a false witness."

The Prophet (ﷺ) said thrice, "Should I inform you out the greatest of the great sins?" They said, "Yes, O Allah's Messenger (ﷺ)!" He said, "To join others in worship with Allah and to be undutiful to one's parents." The Prophet (ﷺ) 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)