Sahih al-Bukhari 6675
صحيح البخاري#6675SahihNarrated `Abdullah bin `Amr:The Prophet (ﷺ) said, "The biggest sins are: To join others in worship with Allah; to be undutiful to one's parents; to kill somebody unlawfully; and to take an oath Al-Ghamus
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 83:53