All things bear record · 2 Corinthians
4 witnesses of Christ here, and 1 further echo from the reading.
Christ — the Anointed One
Since ye seek a proof of Christ speaking in me, which to you-ward is not weak, but is mighty in you. 2 Corinthians 13:3
Some Corinthians wanted proof that Christ really speaks through Paul. An apostle speaks for the Savior, and His power is mighty among the Saints.
How we know: the verse itself names Him
For though he was crucified through weakness, yet he liveth by the power of God. For we also are weak in him, but we shall live with him by the power of God toward you. 2 Corinthians 13:4
"He" is Christ, who was crucified in mortal weakness and now lives by the power of God. Because He rose, disciples who are weak in Him will also live with Him.
How we know: a footnote points to Him · a Church study aid lists it
Jesus Christ — Jehovah saves, the Anointed One
Examine yourselves, whether ye be in the faith; prove your own selves. Know ye not your own selves, how that Jesus Christ is in you, except ye be reprobates? 2 Corinthians 13:5
Paul invites the Saints to test their own faith. A true disciple can know that Jesus Christ lives in him.
How we know: the verse itself names Him
Therefore I write these things being absent, lest being present I should use sharpness, according to the power which the Lord hath given me to edification, and not to destruction. 2 Corinthians 13:10
Paul's power as an apostle comes from the Lord and is meant to build up, not destroy.
Jesus Christ — Jehovah saves, the Anointed One
The grace of the Lord Jesus Christ, and the love of God, and the communion of the Holy Ghost, be with you all. Amen. 2 Corinthians 13:14
Paul's closing blessing names the grace of Jesus Christ alongside the love of the Father and the fellowship of the Holy Ghost, three distinct members of the Godhead.
How we know: the verse itself names Him