Abu Bakra reported,

The Prophet ﷺ said, "Shall I not inform you of the gravest of major sins?" He repeated this three times.They said, "Yes, Messenger of Allah."He said, "Associating partners with Allah, and disobedience to parents."He had been reclining, but then he sat up and said, "And beware of false speech."He kept repeating it until we wished he would stop.

Azami 12795

Sahih

عن أبي بكرة قال

قال النبي ﷺ: ألا أنبئكم بأكبر الكبائر؟ ثلاثا. قالوا: بلى، يا رسول الله. قال: الإشراك بالله، وعقوق الوالدين. وجلس، وكان متكئا، فقال: ألا وقول الزور. قال: فما زال يكررها حتى قلنا: ليته سكت.

الأعظمي 12795صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Tafsir of the great Quran
Chapter
Tafsir of Surah Anbiya
Section
His saying, "That, and whoever honors the sacred ordinances of Allah, it is best for him in the sight of his Lord. And permitted to you are the grazing livestock except what is recited to you. So avoid the uncleanliness of idols and avoid false"
Numbering
Jami al-Kamil 12795 (2nd edition)