The doctrine of the Trinity is foundational to the Christian faith. It is crucial for properly understanding what God is like, how He relates to us, and how we should relate to Him. But it also raises many difficult questions. How can God be both one and three? Is the Trinity a contradiction? If Jesus is God, why do the Gospels record instances where He prayed to God?
While we cannot fully understand everything about the Trinity (or anything else), it is possible to answer questions like these and come to a solid grasp of what it means for God to be three in one.
What Does it Mean That God is a Trinity?
The doctrine of the Trinity means that there is one God who eternally exists as three distinct Persons--the Father, Son, and Holy Spirit. Stated differently, God is one in essence and three in person. These definitions express three crucial truths: (1) The Father, Son, and Holy Spirit are distinct Persons, (2) each Person is fully God, (3) there is only one God.
The Father, Son, and Holy Spirit are distinct Persons. The Bible speaks of the Father as God (Phil. 1:2), the Jesus as God (Titus 2:13), and the Holy Spirit as God (Acts 5:3-4). Are these just three different ways of looking at God, or simply ways of referring to three different roles that God plays?
The answer must be no, because the Bible also indicates that the Father, Son, and Holy Spirit are distinct Persons. For example, since the Father sent the Son into the world (John 3:16), He cannot be the same person as the Son. Likewise, after the Son returned to the Father (John 16:10), the Father and the Son sent the Holy Spirit into the world (John 14:26; Acts 2:33). Therefore, the Holy Spirit must be distinct from the Father and the Son.
In the baptism of Jesus, we see the Father speaking from heaven and the Spirit descending from heaven in the form of a dove as Jesus comes out of the water (Mark 1:10-11). In John 1:1 it is affirmed that Jesus is God and, at the same time, that He was "with God"-thereby indicating that Jesus is a distinct Person from God the Father (cf. also 1:18). And in John 16:13-15 we see that although there is a close unity between them all, the Holy Spirit is also distinct from the Father and the Son.
The fact that the Father, Son, and Holy Spirit are distinct Persons means, in other words, that the Father is not the Son, the Son is not the Holy Spirit, and the Holy Spirit is not the Father. Jesus is God, but He is not the Father or the Holy Spirit. The Holy Spirit is God, but He is not the Son or the Father. They are different Persons, not three different ways of looking at God.
The personhood of each member of the Trinity means that each Person has a distinct center of consciousness. Thus, they relate to each other personally--the Father regards Himself as "I," while He regards the Son and Holy Spirit as "You." Likewise the Son regards Himself as "I," but the Father and the Holy Spirit as "You."
Often it is objected that "If Jesus is God, then he must have prayed to himself while he was on earth." But the answer to this objection lies in simply applying what we have already seen. While Jesus and the Father are both God, they are different Persons. Thus, Jesus prayed to God the Father without praying to Himself. In fact, it is precisely the continuing dialog between the Father and the Son (Matthew 3:17; 17:5; John 5:19; 11:41-42; 17:1ff) which furnishes the best evidence that they are distinct Persons with distinct centers of consciousness.