He hath put a new song into my mouth Both by giving me new matter for a song, and by inspiring me with the very words of it. Many shall see it Shall observe God's wonderful mercies vouchsafed to me; and fear Shall stand in awe of that God, whom they see to have so great power, either to save or to destroy; and shall trust in the Lord Their fear shall not drive them from God, but draw them to him, and be attended with trusting in him.
Related Commentaries of Psalms 40:3
Psalms 40:3
3 And he hath put a new song in my mouth, even praise unto our God: many shall see it, and fear, and shall trust in the LORD.