The Messenger of Allah ﷺ said, "The greatest of major sins are associating partners with Allah, killing a soul, and disobedience to one's parents."
قال رسول الله ﷺ: أكبر الكبائر الإشراك بالله، وقتل النفس، وعقوق الوالدين.
Bukhari narrated it in the Book of Blood Money (6870) from Muhammad bin Bashshar, who said, Muhammad bin Jafar told us, Shubah told us, from Firas, from Shaybi, from Abdullah bin Amr, and he mentioned it.In the same vein is what has been narrated from a man who said, "O Messenger of Allah, what are the major sins?" He said, "They are seven, the greatest of them being associating partners with Allah, killing a person without right, and fleeing on the day of battle."Abu Dawud (2875) and Nasai (4012) both narrated it from the hadith of Muaz bin Hani, who said, Harb bin Shaddad told us, who said, Yahya bin Abu Kathir told us, from Abdul-Hameed bin Sinan, from Ubayd bin Umayr, from his father, who narrated it to him, and he had companionship with the Prophet, that a man said, and he mentioned it, the wording being Nasai's. In its chain is Abdul-Hameed bin Sinan, who is unknown.As for Abu Dawud, he referred it back to the hadith of Abu Hurairah, and said, "They are nine." The hadith of Abu Hurairah is, "Avoid the seven destructive sins," and Abu Dawud added, "and undutifulness to Muslim parents, and violating the sanctity of the Sacred House, which is your direction of prayer, both in life and in death."