A short reply regarding not only our triune nature but my thoughts on the triune nature of God, which my debater rejects.
1 Thessalonians 5:23
And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.
As each individual can speak of himself “as One” but in actual fact is in a way ‘triune’, so I believe the same can be said about our God who is Father, Son and The Holy Ghost.
Hear, O Israel: The Lord our God is one Lord:
Thou believest that there is one God; thou doest well: the devils also believe, and tremble.
I lean heavily towards believing that it is the spirit breathed into Humanity at the beginning [Gen 2:7] and is passed on to Adam’s descendants that holds each individual in life, even in our triune state where a soul is clothed with a body which unravels at the point of death.
6 Or ever the silver cord _[spirit that binds us in our triune state]_ be loosed, or the golden bowl be broken, or the pitcher be broken at the fountain, or the wheel broken at the cistern.
7 Then shall the dust [body] return to the earth as it was: and the spirit [Lk 23:46] shall return unto God who gave it. [Gen 2:7]
And of course, before all sin was accounted for at the Cross all descended into Hades to await judgement [Heb 9:27] and a certain sentencing to hell, but now so long after, not all, but the damned only who chose to die in their sin.
He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God.
Reflecting on these things while being aware that we are in some way made in God’s image...
And God said, Let us make man in our image, after our likeness:...
I ponder the many scriptures that not only state that Jesus is in the Father and the Father in the Son...
Believest thou not that I am in the Father, and the Father in me? the words that I speak unto you I speak not of myself: but the Father that dwelleth in me, he doeth the works.
But that they can both be in us...
Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him.
Without going into any great detail, this appears to be accomplished through the nature of God the holy Spirit.
Studying this subject opens-up so much and I wouldn't for a moment pretend I understand it all but have found it a very fruitful path to ponder.
My habit is to back-up what I believe with scripture, not to state that what I believe is unquestionably true but rather that other readers have the opportunity to test what I have stated, who can thereafter either correct me else validate that both maybe edified. This should always be our intention, to the edification of others that God should be exalted and not man.