David
Psalm 138:5ESV·traditional attribution

and they shall sing of the ways of the LORD, for great is the glory of the LORD.

John Calvin Reformed @genevareformer

PSALM 138 In this Psalm David, in remembrance of the singular help which had always been vouchsafed him by God — the experience he had enjoyed of his faithfulness and goodness, takes occasion to stir himself up to gratitude; and from what he had known of the divine faithfulness, he anticipates a continuance of the same mercy. If dangers must be met, he confidently looks for a happy issue.

Commenting on Psalm 138:1-8

C.H. Spurgeon Reformed Baptist @princeofpreachers

Yea, they shall sing in the ways of the Lord. Here is a double wonder—kings in God's ways, and kings singing there. Let a man once know the ways of Jehovah, and he will find therein abundant reason for song; but the difficulty is to bring the great ones of the earth into ways so little attractive to the carnal mind.

Matthew Henry Presbyterian @wholebiblehenry

I. How he would praise God, compare Psa 111:1. 1. He will praise him with sincerity and zeal - "With my heart, with my whole heart, with that which is within me and with all that is within me, with uprightness of intention and fervency of affection, inward impressions agreeing with outward expressions." 2.

Commenting on Psalm 138:1-5