The signal victories given to David exalted the power of Israel’s God before the nations. Paul quotes this verse to illustrate how the knowledge of God would go to the Gentiles through the preaching of the gospel (Rom. 15:9). God planned that Israel should be His evangel of salvation. The psalmist frequently spoke of the glory that would come to Israel if she would accomplish her high destiny. He looked forward to the time when all the earth would worship God and sing praises to Him (Ps. 66:4), and when all the kings of the earth would fall down before Him and all nations would serve Him (Ps. 72:11). Hence the psalmist called upon Israel to “declare among the people his doings” (Ps. 9:11) and “his glory among the heathen” (Ps. 96:3), and expressed his own intention to praise God among the people and to sing unto Him among the nations (Ps. 57:9). See also Ps. 105:1; Isa. 12:4.

The “therefore” links David’s giving of thanks to the preceding narration of God’s mercies to him. The secret of David’s deep religious experience lay in the fact that he constantly kept in mind the mercies he had received from God and never ceased thanking the Lord for them.