Is the Trinity really biblical?

While the word “Trinity” is not itself given in Sacred Scripture, the Church determined that the term taught the truth about the God whom Scripture reveals—One God and Three Divine Persons. Many other terms (e.g. Incarnation, Person, Sacrament) have been used over the centuries to teach revealed truths, having acquired stable meanings from consistent use or Church decision. In this way, the Church’s doctrines are able to teach true things about a mystery of God, without intending to exhaust all that might be said about that mystery.

Fifty references to the Trinity in Scripture:

What is the Trinitarian formula for baptism?

The Catechism of the Catholic Church (paragraph 233) says,

Christians are baptized in the name of the Father and of the Son and of the Holy Spirit: not in their names, for there is only one God, the almighty Father, his only Son and the Holy Spirit: the Most Holy Trinity.

The Trinitarian formula is so central to the Christian sacrament of baptism (Mt. 28:18-20), and thus of justifying the sinner (Acts 2:38), that the Church rejects all other formulas as invalid, that is, not accomplishing the purposes of Baptism. This includes “the baptism of John“ (Acts 18:25), baptism in the “name of Jesus” (mistaking the euphemism for being baptized into Christ as a formula), or, in our own day, baptism “in the Name of the Creator, Redeemer and Sanctifier.”