Sahih Bukhari

Narrated Abu Bakra:Allah's Messenger (ﷺ) said thrice, ""Shall I not inform you of the biggest of the great sins?"" We said, ""Yes, O Allah's Messenger (ﷺ)"" He said, ""To join partners in worship with Allah: to be undutiful to one's parents."" The Prophet (ﷺ) sat up after he had been reclining and added, ""And I warn you against giving forged statement and a false witness; I warn you against giving a forged statement and a false witness."" The Prophet kept on saying that warning till we thought that he would not stop