Surah Az-Zumar 39:2

إِنَّآ أَنزَلْنَآ إِلَيْكَ ٱلْكِتَـٰبَ بِٱلْحَقِّ فَٱعْبُدِ ٱللَّهَ مُخْلِصًا لَّهُ ٱلدِّينَ

Indeed, We have sent down to you the Book, [O Muḥammad], in truth. So worship Allāh, [being] sincere to Him in religion.

Translation: Saheeh International

Tafsir

Indeed We have revealed to you O Muhammad (s) the Book with the truth bi’l-haqqi is semantically connected to anzalnā ‘We have revealed’; so worship God devoting your religion purely to Him pure of any idolatry in other words affirming His Oneness.

Excerpt from Tafsir al-Jalalayn, commentary on 39:2, via Quran.com. The reader has the full commentary and 9 more tafsirs.