The word Trinity is never used in Scripture. It’s a man devised term, the definition of which is the person, or persons, it indicates. One God in three persons – The Father, The Son, The Holy Spirit. Each has different jobs to do, yet each is the same one God. “I and the Father are one.” The Spirit lives inside of the saved person. Jesus lives inside the saved person. God the Father lives inside the saved person. Yet the Son sits on the right hand of the Father making intercession for the believers, those God the Father has given God the Son, while the Spirit works within the believer to sanctify him (or her) – bring him or her to the sinless image of the Son. The Son died on the cross for our sins then the Spirit, the Son Himself, The Father, raised Him from the dead, conquering death. “This is my Son in whom I am well pleased,” Said the Father of the Son, yet “I and the Father are one.” “If you’ve seen me, you’ve seen the Father.”
For me, this is one of the foremost proofs that what we read in the Bible is true, is God breathed, is the one God telling us about Himself and commanding our obedience as the Spirit opens the Scriptures to us. No man could have thought this up, let alone carried this through 66 books of the Bible written by some 40 different men over a 2-thousand-year period without batting an eye, without one blur of confusion, to a point where it’s understood, yet still the greatest of mysteries – the definition is clear, how it works is beyond comprehension. The way it should be with and infinite God. Oh, yes, and to add to the complexity, God the Son is also very God and very man – all God and all man – a hypostatic union of the two – and now sits in His glorified body, the body we’ll have when in heaven, at the right hand of the Father, pleading our case.