The Christian knows God as Trinity. It is the unique revelation that makes our faith true and vital. It’s easy to say you believe in God- but which god? All the gods of the world are but demons, false gods as Deuteronomy has it - so it sure matters which god we are giving our hearts to.
It’s commonplace to hear Christians address, rather casually I think, “God” in their prayers, and apart from the danger of sloppy disrespect, it’s become a habit which belies true worship.
No, the God who has called us to himself is Father, Son and Holy Spirit. The Father ‘thought’ of us in his salvation plan before the foundation of the world; the Son ‘bought’ us with his blood, guaranteeing our salvation and eternal life; and the Spirit ‘wrought’ (worked) in us the effects of such a pleasing choice and costly rescue mission.
The way we know the love of God is through the grace of our Lord Jesus Christ and thus we get to share in the very rich companionship that exists between Father, Son and Holy Spirit, called the fellowship. God in his fullness, before time began, decided to include us in this triune embrace. We get to know God from the inside so to speak, and he is Father, Son and Holy Spirit.
At Jesus’ baptism the very nature of God was revealed for the first time ( hints and suggestions till then): the Father and the Spirit can’t help themselves - the One speaks, the Other tumbles out of heaven in the form of a dove - both eager to stand by the Son, who himself is standing with sinners; as if the Trinity wants us to know that this is where you will find God, with sinners, representing them, and rooting for them so that they can be saved. Alleluia!
Getting to know God as Trinity is just a marvellous voyage into holy Love. The beloved verse “God is love” demands that he be Trinity: there is a Lover (the Father); there is the Beloved (the Son) and there is the Love (the Holy Spirit, no less Personal) between the two. Our immense privilege granted to us in the kindness of God is to get to know God as he really is. It is the adventure of a lifetime and all eternity to seek to know more this God who is both He and They.