"The one true God exists eternally as three persons, coequal in power, glory, and majesty.
Each person has unique roles in creation and salvation, and each person is revealed in Scripture to relate to the others in different ways.
One way the Trinity is important for understanding God is that the Trinity makes it possible for love to be an innate quality of God.
One way the Trinity is important for understanding God is that the Trinity makes it possible for love to be an innate quality of God.
If God was only God the Father, and Jesus came later, for instance, God’s love would be dependent on the existence of creatures for Him
to love.
But because God is a Trinity of three persons, each person loves the other two (i.e., the Father loves the Son and the Spirit, the Son loves the Father and the Spirit, and the Spirit loves the Father and the Son), and each pair jointly loves the third (i.e., the Father and the Son love the Spirit, the Father and the Spirit love the Son, and the Son and the Spirit love the Father)."
AIG