Surah Al-An'am 6:149

قُلْ فَلِلَّهِ ٱلْحُجَّةُ ٱلْبَـٰلِغَةُ ۖ فَلَوْ شَآءَ لَهَدَىٰكُمْ أَجْمَعِينَ

Say, "With Allāh is the far-reaching [i.e., conclusive] argument. If He had willed, He would have guided you all."

Translation: Saheeh International

Tafsir

Say if you have no definitive argument then ‘To God belongs the conclusive argument the perfect one for had He willed to guide you He could have guided all of you’.

Excerpt from Tafsir al-Jalalayn, commentary on 6:149, via Quran.com. The reader has the full commentary and 9 more tafsirs.