Monergism

Scripture testifies from beginning to end that God is one, but it also presents three persons who are God: the Father, the Son and the Holy Spirit. . . . This fact is difficult to understand, but it is quite unavoidable in Scripture and central to the gospel. The doctrine of the Trinity attempts to account for this fact and to exclude heresies that have arisen on the subject. Its basic assertions are these: (1) God is one. (2) God is three. (3) The three persons are each fully God. (4) Each person of the persons is distinct from the others. (5) The three persons are related to one another eternally as Father, Son, and Holy Spirit.
John Frame from The Doctrine of God (pg. 621-22)

The Father...the Son...and the Holy Spirit glorify each other. . . . At the center of the universe, self-giving love is the dynamic currency of the Trinitarian life of God. The persons within God exalt, commune with, and defer to one another. . . . When early Greek Christians spoke of perichoresis in God they meant that each divine person harbors the other at the center of his being. In constant movement of overture and acceptance each person envelops and encircles the others.
Cornelius Plantinga

Ultimate reality is a community of persons who know and love one another. That is what the universe, God, history, and life is all about. . . . We believe the world was made by a God who is a community of persons who have loved each other for all eternity. You were made for mutually self-giving, other directed love. Self-centeredness destroys the fabric of what God has made.
Timothy J. Keller from The Reason for God (pg. 216-15)