John Calvin Commentary Psalms 89:49

"Lord, where are thy former lovingkindnesses, Which thou swarest unto David in thy faithfulness?" — Psalms 89:49 (ASV)

O Lord! Where are Your former mercies? The prophet encourages himself by recalling God’s former benefits, as if his reasoning were that God can never be unlike himself, and that therefore the goodness which he manifested in former times to the fathers cannot come to an end.

This comparison might indeed make the godly despond when they find that they are not dealt with by him so gently as he dealt with the fathers, if another consideration did not at the same time present itself to their minds—the consideration that he never changes and never wearies in the course of his beneficence.

Regarding the second clause of the verse, some interpreters connect it with the first by inserting the relative pronoun, as follows: Where are Your former mercies which You have sworn? I readily agree with this, for the meaning is almost the same, even if the relative pronoun is omitted. God had given evident and indubitable proofs of the truth of the oracle delivered to Samuel; and therefore, the faithful lay before him both his promise and the many happy fruits of it which had been experienced.

They say, in truth, so that they may with greater confidence apply to themselves whatever tokens of his liberality God had in former times bestowed upon the fathers; for they had the same ground to expect the exercise of the Divine goodness towards them as the fathers had, God, who is unchangeably the same, having sworn to be merciful to the posterity of David throughout all ages.