Psalms 66:3

Say unto God, How terrible art thou in thy works! through the greatness of thy power shall thine enemies submit themselves unto thee.

The verse is a song of praise addressed to God in awe at how fearful He is in His works, affirming that through the greatness of His power His enemies shall submit to Him. It belongs to the praise and thanksgiving that should fill the mouth when the love of God is enjoyed in the heart. That praise declares what He has done for the soul, cries to Him with the mouth and extols Him with the tongue. It testifies that God has heard prayer and has not turned away His mercy, bringing forth good things from the treasure of the heart as the fruit of the lips to God.

Psalm 66:1-5, including this verse, was often sung with the voice of singing to welcome the morning beams of light. That singing joined its voice with the praise and thanksgiving of nature, as when listening to the lark carolling its song to its God. By so singing, it taught others to praise God.