Charles H. Spurgeon on Psalms 98:3

He hath remembered his mercy and his truth. The psalmist very properly observes, that God in redeeming the world "remembered his truth, "which he had given to Israel his people —language, too, which implies that he was influenced by no other motive than that of faithfully performing what he had himself promised. The more clearly to show that the promise was not grounded at all on the merit or righteousness of man, he mentions the "mercy" of God first, and afterwards his "faithfulness" which stood connected with it. The cause, in short, was not to be found out of God himself, (to use a common expression,)but in his mere good pleasure, which had been testified long before to Abraham and his posterity. The word "remembered" is used in accommodation to man's apprehension; for what has been long suspended seems to have been forgotten. Upwards of two thousand years elapsed from the time of giving the promise to the appearance of Christ, and as the people of God were subjected to many afflictions and calamities, we need not wonder that they should have sighed, and given way to ominous fears regarding the fulfilment of this redemption. John Calvin.