"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)
The doctrine of the triune God is unique to Christianity. There is only one God, yet three Persons--Father, Son, and Holy Spirit--each with His own distinct relation to mankind, yet each equally, fully, and eternally God. Although these truths are implicit throughout the New Testament, the doctrine of the Trinity is seldom, if ever, presented therein explicitly as a formal doctrine.
There are several passages, however, where all three Persons are mentioned in the same context, and each one deals with a significant aspect of the Christian life. There is, first of all, the provision of salvation, ". . . the blood of Christ, who through the eternal Spirit offered himself without spot to God" (Hebrews 9:14). Then follows regeneration. "And because ye are sons, God hath sent forth the Spirit of his Son into your hearts, crying, Abba, Father" (Galatians 4:6). Salvation and regeneration are then publicly testified in baptism "in the name of the Father, and of the Son, and of the Holy Ghost" (Matthew 28:19).
The chief resource of the believer is prayer, and this also involves all three Persons. "For through |Christ| we both have access by one Spirit unto the Father" (Ephesians 2:18). He must also continue to learn of Christ, and to bear witness of Him. "The Holy Ghost, whom the Father will send in my name, he shall teach you all things" (John 14:26). "The Spirit of truth, which proceedeth from the Father, he shall testify of me: And ye also shall bear witness" (John 15:26-27).
Finally, in the words of our text, we have eternal assurance in the triune God. "The grace of the Lord Jesus Christ, and the love of God, and the communion of the Holy Ghost, be with you all. Amen." HMM