When verse 5 recently struck me, I guess for the first time (although I have read it several times in the past) it struck hard. The Holy Spirit (which is apparently the spirit referred to) is jealous? I checked some other versions of the Bible:
5 Do ye think that the scripture saith in vain, The spirit that dwelleth in us lusteth to envy? (KJV)
The answer seems to be that the Spirit can be jealous, indeed.
Thanks for reading.