These are my intuitions.
I would suggest that it is the spirit of a man that gives him life, and in the first creation the life/spirit is in the body, in the blood; that is, it enlivens the blood which enlivens the body. I would suggest that that blood-enlivening spirit is innocent and clean at birth, but our departing from innocence later in life muddies/confuses/pollutes/corrupts the blood-enlivening spirit with a degree of bias toward self-reliance rather than faith toward God. In the new birth God puts a new pure and incorruptible spirit into our soul, which enlivens our mind with revelation truth, and enables us to subdue the spirit in our blood, if we so choose.
We need that new incorruptible spirit because the original blood-enlivening spirit is weaken and handicapped by our flesh, so that we often cannot do the good we want to do. That's why we need a new spirit even though we already have one. Yes, we get both spirits from God. If we do not have an upgraded spirit, when our original spirit leaves our blood, we die physically and our soul goes with it to hades. to await judgment. However, of we have an upgraded spirit as well, then when our upgraded spirit leaves our body, our soul goes with it into God's presence.