James 4:3 Ye ask, and receive not, because ye ask amiss, that ye may consume it upon your lusts.
4 Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God.
5 Do ye think that the scripture saith in vain, The spirit that dwelleth in us lusteth to envy?
6 But he giveth more grace. Wherefore he saith, God resisteth the proud, but giveth grace unto the humble.
8 Draw nigh to God, and he will draw nigh to you. Cleanse your hands, ye sinners; and purify your hearts, ye double minded.
Of course it is speaking of the spirit of people because it is speaking of lust of the flesh that people do.
This has to do with lusting for things of the flesh which God tells them to correct it so it would not be speaking of the Jesus being jealous over His chosen.
James 4:5 Or do you think that the Scripture says in vain, "The Spirit who dwells in us yearns jealously"?
This would be the wrong interpretation for it is not speaking of the Spirit but the spirit in people.
The context is lust of the flesh so it speaking of the spirit of people that lust.
Which is strange how it is the New King James version but strays like like that from the King James version.