What is Trinity?

Trinity is a terminology that is not found in the Bible but used to aid our understanding of the Godhead - the Father, the Son and the HS. And we understand from the Bible that these three are one. 

In the beginning we understand that God the Father used the word 'let us'.

It is easy to understand and it is wisdom. The same way it was for man that the woman was taken out of man and the two remain as one, so it is with the son and HS with the Father. Wisdom presented 3 personalities in the Godhead to us in redemption. 

Roles 

The Father proposes. 

The Son arranges the order of things. 

The HS accomplishes it (Job 26:5, Ps 104:29). 

The Father approves it (it is good). 

The Father is not complete as Godhead without the Son and the Spirit. 

The Spirit is an aspect of Godhead formed into a whole. The HS is the power of God. 

The Word is an aspect of Godhead formed into a whole (Proverb 28:22-23). The word is the wisdom of God. 

The Father is the head; both the HS and Son are subject to the Father and all the 3 of them are one 

The Father is always in need of companion. 

Both the Spirit and the Son cannot leave Him at the same time. When one is on assignment the other stays with Him. 

When Jesus was sent, both the Father and the Spirit were together (Isaiah 48:16). 

Before the HS was released to commence His ministry, Jesus had to go to the Father. In the beginning when the HS was hovering the face of the sea, the Son was with the Father (Genesis 1:2, Proverb 8:30, John 1:1,3).  

The ministry of HS. 

Monitoring and ensuring what God has set in place. 

There is no difference between OT & NT manifestations of HS but some things are different- God was far away in OT but very near in NT, so most things were known in minute part in OT but in NT we know better (it is just a matter of how much understanding man is capable of knowing). 

However for the HS, it does not matter if God was far away or near, He does His work (people of faith still received Christ even before he came, Hebrews11:23-26) thereby producing fruit. But the closeness to God matters to man- hope, assurance of the promises of God, fulfilment of Gods promises; making it possible for the weak to understand God (expanding the kingdom of God). 

In the NT we understand that our spirits were recreated, they became alive, able to relate with God. Likewise, we understand that the HS now dwells in us.

Keys

HS- Holy Spirit

OT- Old Testament

NT- New Testament