“The three Biblical doctrines that flow directly into the river that is the Trinity are as follows:
1. There is one and only one God, eternal, immutable.
2. There are three eternal Persons described in Scripture—the Father, the Son, and the Spirit. These Persons are never identified with one another—that is, they are carefully differentiated as Persons.
3. The Father, the Son, and the Spirit, are identified as being fully deity—that is, the Bible teaches the Deity of Christ and the Deity of the Holy Spirit.” (James White)
For more on the subject, visit the Systematic Theology page.