Is the Trinity something we just came up with using the Father Son and the Holy Spirit or is it really mentioned in the Holy Bible as the Trinity?
Although the term Trinity does not appear in the New Testament, however, "Father, Son and Holy Spirit" appear repeatedly "For there are three that bear record in heaven, the Father, the Word" (St John refers to the Lord Jesus Christ as the Word - the Logos; John 1:1) and the Holy Spirit, and these three are one" (1 John 5:7). In the Great Commission, at the close of the Holy Gospel of St Matthew, the Lord Jesus Christ commands His disciples to baptize "In the name of the Father, and of the Son, and of the Holy Spirit" (Matthew 28:19). St. Paul, St. Peter and St. Jude enumerate the three persons of the Godhead "The grace of the Lord Jesus Christ, and the love of God, and the communion of the Holy Ghost, be with you all" (2 Corinthians13:14); "According to the foreknowledge of God the Father, through sanctification of the Spirit, unto obedience of the blood of Jesus Christ" (1 Peter 1:2);"To them that are sanctified by God the Father, and preserved in Jesus Christ ... praying in the Holy Spirit, keep yourselves in the love of God, looking for the mercy of our Lord Jesus Christ unto eternal life" (Jude 1,20,21).
The need to elaborately define the Godhead came at the end of the first century when the Gnostic heretics caused division through their pagan-influenced teaching that the Lord Jesus Christ or LOGOS (John 1:1) was a lesser god. This threat caused the early Church to adopt a comprehensive creed called the Apostle's Creed consisting of twelve apostolic statements of faith derived both from written scripture and oral teaching passed down from the first century Apostles. Trinitarianism was a doctrine taught by the Apostolic Fathers. They received their tradition from the Twelve Apostles and the Apostle Paul. The doctrine was handed down orally from the time of the first century in the form of creeds, apostolic catechisms, or written symbols. In exposition to the scriptures, we find a strong Trinitarian tradition at the end of the first century and the beginning of the second century in the writings of the Apostolic Fathers and the Apologists. We believe that the writings of the Apostolic Fathers contain teachings entrusted to them by the New Testament Apostles. The Apostolic Fathers had a developed doctrine of the Trinity. This doctrine was handed down from the Apostles of the Lord Jesus Christ to the Apostolic Fathers of the second century (96 AD to 175 AD). A developed Trinitarian doctrine existed in the church well before 175 AD (the time of Tertullian's writing). This doctrine existed in Christian writings a full generation before this time.