1 “For Salomon” indeed this Psalm's title is fore-noted: but things are spoken of therein which could not apply to that Salomon king of Israel after the flesh, according to those things which holy Scripture speaks concerning him: but they can most pertinently apply to the Lord Christ. Whence it is perceived, that the very word Salomon is used in a figurative sense, so that in him Christ is to be taken. For Salomon is interpreted peace-maker: and on this account such a word to Him most truly and excellently does apply, through Whom, the Mediator, having received remission of sins, we that were enemies are reconciled to God. For “when we were enemies we were reconciled to God through the death of His Son.” The Same is Himself that Peace-maker....Since then we have found out the true Salomon, that is, the true Peace-maker: next let us observe what the Psalm does teach concerning Him.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)