On this subject, though, I came across some colloquial language in Fielding's Tom Jones which may give insight into the relation of spirit to soul. A landlady had mistaken a lady for a whore and effusively apologized and the lady responded (when offered something of the landlady's to wear):
"...I will [not] condescend to put on any of your dirty things. I would have you know, creature, I have a spirit above that."Now, pay no attention to the affectation of being 'better' than others here, I am getting at the natural, colloquial language of which Fielding is good at reproducing. "I have a spirit above that."
In this sense spirit is the quality of the soul. Something overly pious, or fake modest Christians object to is any talk of degree of level of being of believers, even though the Word of God speaks explicitly of it. But that is neither here nor there regarding the point of this post.
There is body and soul. That is what we are. Then our spirit is the quality of the soul. Not in the sense of being an abstraction (quality); it is a thing, the Spirit itself, of which Jesus only had/has the full measure (itself a reference to degree of level of being in reference to spirit); so then also our spirit develops, in the fullness of time, by the grace of God.