The doctrine of the Trinity is the belief that there is only one living and true God. Yet, the one God is three distinct Persons: God the Father, God the Son, and God the Holy Spirit. These three have distinct personal attributes, but without division of nature, essence, or being. They enjoy eternal communion and are coeternal and coequal.
The doctrine of the Trinity denies tritheism. Tritheism is the belief that there are three gods. There is only one God. The doctrine of the Trinity also refutes modalism. Modalism is the belief that God is only one Person who appears in different modes at different times. The three Persons of the Trinity exist simultaneously. They are distinct and eternal Persons in the one God.
While the word "Trinity" is not found in the Bible, its truth is expressed in many biblical passages. The Bible recognizes the Father as God, the Son as God, and the Holy Spirit as God.
What follows these paragraphs is a bludgeoning array of Bible quotes that purport to show how the three-in-one isn't an utterly incoherent concept invented by theologians to explain away inconsistencies in Christian scripture. The last paragraph of the chapter reads:
The only conclusion is that the Christian doctrine of the Trinity accurately describes the biblical testimony about God. Finite humans cannot rationally explain the doctrine of the Trinity. This should not surprise us since there are many things the Bible teaches about God that we cannot fully understand. For example, the Bible affirms the existence of God, the creation of the universe, atonement from sin, and the resurrection of the dead although none of the truths can be totally understood by finite minds. As with the doctrine of the Trinity, Christians do not accept these teachings because they can rationally explain them, but because the Bible teaches them.
As it is, this chapter leaves me with the impression that there are three degrees (indeed, a trinity) of mendacity: lies, damned lies, and theology.