2 Corinthians 13:14
The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit, be with you all. (NASB, 1995)
This passage constitutes a prayer to all 3 members of the Trinity.
a. Frederick Danker: This benediction is the climax of Paul's closing prayerful approach that had begun at v. 7 (2 Corinthians, Augsburg Commentary on the New Testament, page 213).
b. Albert Barnes: In regard to this closing verse of the Epistle, we may make the following remarks:
(1) It is a prayer; and if it is a prayer addressed to God, it is no less so to the Lord Jesus and to the Holy Spirit. If so, it is right to offer worship to the Lord Jesus and to the Holy Spirit.
(2) there is a distinction in the divine nature; or there is the existence of what is usually termed three persons in the Godhead. If not, why are they mentioned in this manner? If the Lord Jesus is not divine and equal with the Father, why is he mentioned in this connection? How strange it would be for Paul, an inspired man, to pray in the same breath, "the grace of a man or an angel" and "the love of God" be with you! And if the "Holy Spirit" be merely an influence of God or an attribute of God, how strange to pray that the "love of God" and the participation or fellowship of an "influence of God," or an "attribute of God" might be with them!
(3) the Holy Spirit is a person, or has a distinct personality. He is not an attribute of God, nor a mere divine influence. How could prayer be addressed to an attribute, or an influence? But here, nothing can be plainer than that there were favors which the Holy Spirit, as an intelligent and conscious agent, was expected to bestow. And nothing can be plainer than that they were favors in some sense distinct from those which were conferred by the Lord Jesus, and by the Father. Here is a distinction of some kind as real as that between the Lord Jesus and the Father; here are favors expected from him distinct from those conferred by the Father and the Son; and there is, therefore, here all the proof that there can be, that there is in some respects a distinction between the persons here referred to and that the Holy Spirit is an intelligent, conscious agent.
(4) the Lord Jesus is not inferior to the Father, that is, he has an equality with God. If he were not equal, how could he be mentioned, as he here is, as bestowing favors like God, and especially why is he mentioned first? Would Paul, in invoking blessings, mention the name of a mere man or an angel before that of the eternal God?
(5) the passage, therefore, furnishes a proof of the doctrine of the Trinity that has not yet been answered, and, it is believed, cannot be. On the supposition that there are three persons in the adorable Trinity, united in essence and yet distinct in some respects, all is plain and clear. But on the supposition that, the Lord Jesus is a mere man, an angel, or an archangel, and that the Holy Spirit is an attribute, or an influence from God, how unintelligible, confused, strange does all become! That Paul, in the solemn close of the Epistle, should at the same time invoke blessings from a mere creature, and from God, and from an attribute, surpasses belief. But that he should invoke blessings from him who was the equal with the Father, and from the Father himself, and from the Sacred Spirit sustaining the same rank, and in like manner imparting important blessings, is in accordance with all that we should expect, and makes all harmonious and appropriate.
http://www.studylight.org/commentaries/bnb/2-corinthians-13.html#1