Then how is it that God could send His spirit to dwell & abide within an individual human being, within a soul as it were?
When it was given to John the Baptist to witness the Holy Spirit descend upon Christ and remain there -- was not Jesus then 'a soul' prior to that moment? (and afterwards also, of course)
John 3:8-10 (AKJV)
8 The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit.9 Nicodemus answered and said unto him, How can these things be? 10 Jesus answered and said unto him, Art thou a master of Israel, and knowest not these things?
I said spirit not Holy Spirit... try to keep up. The Holy spirit is the Third person of the Trinity.