It is only natural at this point to try and think of illustrations or analogies to try and describe the Trinity, as the three states of H2O. However, no analogy can perfectly portray the Trinity. For example, H2O exists only in the three separate modes of liquid (water), solid (ice), and gas (vapor). Yet, the Godhead is the Father, the Son, and the Spirit all at once. He does not change into each mode depending on His function or mood. All three exist at once and all three are shown to be present at Jesus’ baptism “As soon as Jesus was baptized, he went up out of the water. At that moment heaven was opened, and he saw the Spirit of God descending like a dove and alighting on him. And a voice from heaven said, ‘This is my Son, whom I love; with him I am well pleased.’” (Matthew 3:16-17) The members of the Trinity are mutually indwelling withing each other. This means they even have an interpenetration, (while not diminishing their personhood) which does reveal an aspect of their oneness. This does not mean the persons of the Trinity are a characteristic or a part of the true God, such that God only exists as the three together. Each person is fully God and there is no common quality of divinity that exists separate from Father, Son, and Spirit. An example of this is when Jesus says, “Don’t you believe that I am in the Father, and that the Father is in me?” (John 14:10)
So how do the members of the Trinity relate to one another? The Father begets the Son, who is “begotten but not made”, and the Spirit processes from the Father (and the Son). So, what does this mean?
The phrase “begotten but not made” comes again from the Nicene Creed. When it is said Jesus, the Son of the Father, is “begotten”, the word “begotten” is not to be understood literally. It is a relational figure of speech that means Jesus is the unique (one and only) Son of the Father. If Jesus were made, God could not fully love creation. Michael Reeves, in his book Delighting in the Trinity, put it this way:
“God the Father is a God who delights to have another beside him (his eternal Son). He is a God who thinks that is good. And thus he is a God who can declare his creation good. If he had been eternally alone, preoccupied with himself, it is hard to believe he could do that. The new existence of something else beside him would surely be a nuisance, or perhaps appear to be a rival.”
When the Father sends the Spirit in John 14:26, this is the “procession”. It reads, “But the Advocate, the Holy Spirit, whom the Father will send in my name, will teach you all things and will remind you of everything I have said to you.” In John 15:26 and 20:22, Jesus joins in the sending of the Spirit. These relations are how the members interact with each other.
Furthermore, the Bible reveals two completed missions of God the Father. One for the Son and one for the Spirit. Something to note here is that both the Son and the Spirit submit to the Father, but that does not mean they are subordinate to the Father. You may remember from my last post each member is equal in authority, power, and nature. Both missions have the aim of adding to the family of God. All believers are brothers and sisters of Christ and joint-heirs of the Father (Galatians 4:4-7). But each mission is distinct. The Father’s mission for the Son was for him to become flesh in the world (John 1:14), which made him the only God-man, fully God (Colossians 2:9) and fully man (1 Timothy 2:5). The Father’s mission for the Spirit was to be sent as the helper, advocate, comforter, and counselor of the church (John 14-17). He was to indwell, fill, and prepare believers.