O Lord! where are thy former mercies? The prophet encourages himself, by calling to remembrance 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 old time 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, did not another consideration at the same time present itself to their minds -- the consideration that he never changes, and never wearies in the course of his beneficence. As to the second clause of the verse, some interpreters connect it with the first, by interposing the relative, thus: -- Where are thy former mercies which thou hast sworn? In this I readily acquiesce; for the sense is almost the same, although the relative be 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, that they may with the greater confidence apply to themselves, whatever tokens of his liberality God had in old time 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.

Lord, where are thy former loving-kindnesses - Thy mercies; thy pledges; thy promises. Where are those promises which thou didst make formerly to David? Are they accomplished? Or are they forgotten and disregarded? They seem to be treated as a thing of nought; as if they had not been made. He relied on them; but they are not now fulfilled.
Which thou swarest unto David - Which thou didst solemnly promise, even with the implied solemnity of an oath.
In thy truth - Pledging thy veracity.

Lord, where are thy former lovingkindnesses - Wilt thou not deal with us as thou didst with our fathers? Didst thou not swear unto David that thou wouldst distinguish him as thou didst them?

Lord, where are thy former lovingkindnesses,.... The spiritual blessings said to be in Christ; the grace said to be given to us in him; the sure mercies of David, such as redemption, justification, remission of sins, and eternal life; so called because they flow from the free favour and love of God, and, being many, are expressed in the plural number; and which were former or ancient ones, even promised and secured in Christ before the world began; springing from the love of God, which, both to Christ and his people, was from everlasting, and provided for in a covenant, which was as early:
which thou swarest unto David in thy truth? which were promised to Christ, the antitype of David, and that with an oath, by the truth or faithfulness of God, for the certainty thereof: but now where are all these? or how will they take place, if Christ rise not from the dead? where will be the redemption of his people, the justification of their persons, the remission of their sins, and their everlasting salvation? and what will become then of the covenant, oath, and faithfulness of God?

The terms of expostulation are used in view of the actual appearance that God had forsaken His people and forgotten His promise, and the plea for aid is urged in view of the reproaches of His and His people's enemies (compare Isaiah. 37:17-35).