Abdullah bin Masud reported,

I asked the Prophet ﷺ, "Which sin is greatest in the sight of Allah?"He replied, "That you set up a rival to Allah, while it is He who created you."I said, "That is indeed a grave sin. Then which?"He said, "That you kill your child out of fear that he will eat with you."I asked, "Then which?"He answered, "That you commit adultery with your neighbor's wife."

Azami 11891

Sahih

عن عبد الله بن مسعود قال

سألت النبي ﷺ: أي الذنب أعظم عند الله؟ قال: أن تجعل الله ندا وهو خلقك قلت: إن ذلك لعظيم، قلت: ثم أي؟ قال: وأن تقتل ولدك تخاف أن يطعم معك قلت: ثم أي؟ قال: أن تزاني حليلة جارك

الأعظمي 11891صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Tafsir of the great Quran
Chapter
Virtues of Surah Baqarah
Section
His saying, "O people, worship your Lord who created you and those before you, that you may become righteous. He who made for you the earth a bed and the sky a ceiling, and sent down from the sky rain, and brought forth thereby fruits as provision for you. So do not attribute to Allah equals while you know."
Numbering
Jami al-Kamil 11891 (2nd edition)
Azami 11891