The Doctrine of the Trinity is mysterious. I am not surprised that it is perplexing. The Christian church has always confessed that the One God exists in three persons; Father, Son and Holy Spirit. These three are one, and yet exist in three separate persons. Jesus prayed to God, His Father. Jesus is now sitting at the right hand of God, His Father. When Jesus hung dying on the cross he was forsaken of God, His Father.
The Athanasian Creed is the best summary of the doctrine of the Trinity. God eternally exists in one essence and three distinct persons. The persons of the Trinity are distinguishable in both their person and their function. Robert Reymond summarizes the essential doctrine of the Trinity in this way. “Three propositions (or doctrines) are essential to the Christian doctrine of the Trinity: (1) there is but one living and true God who is eternally and immutably indivisible (the doctrine of monotheism); (2) the Father, the Son, and the Holy Spirit are each fully and equally God (the doctrine of the three Persons’ “sameness in divine essence,” and (3) the Father, the Son, and the Holy Spirit are each distinct Persons (the doctrine of the three Persons’ “distinctness in subsistence).” The three errors that this summary guards against are tritheism (there are 3 Gods); subordinationism (the persons of the Trinity are not equal in power and glory); and modalism (God appears in three ways at different times but is really only one God in different forms.
John Frame captures the practical importance of the Trinity for the Christian. “As we meditate on the different, but unified roles of the three persons in saving us, we are driven back to worship. We are saved by the eternal purpose of the Father, by the atoning work of the Son, through the power and wisdom of the Spirit. We grow in our understanding of God’s grace as we see how each person of the Trinity interacts with the others to bring us out of darkness and into the light.”