The Faithful 'Bride'

Numbers 5 starts out with a summary of uncleanness - and its consequence being a casting of those individuals outside the camp

then follows on to the sacrifice of atonement by the ram for confession of sins and a restitution of the sins

then comes to this very weird bit on the unfaithful wife:
- if she hides her adultery, she is judged, and cursed

Numbers 5:12-14 12 "Speak to the people of Israel, If any man's wife goes astray and breaks faith with him, 13 if a man lies with her sexually, and it is hidden from the eyes of her husband, and she is undetected though she has defiled herself, and there is no witness against her, since she was not taken in the act, 14 and if the spirit of jealousy comes over him and he is jealous of his wife who has defiled herself, or if the spirit of jealousy comes over him and he is jealous of his wife, though she has not defiled herself,

This is possibly the reference that James is taking here:
James 4:4-6 4 You adulterous people! Do you not know that friendship with the world is enmity with God? Therefore whoever wishes to be a friend of the world makes himself an enemy of God. 5 Or do you suppose it is to no purpose that the Scripture says, "He yearns jealously over the spirit that he has made to dwell in us"? 6 But he gives more grace. Therefore it says, "God opposes the proud, but gives grace to the humble."

The Spirit of God yearns jealously over His Bride
the adultery of the bride angers the groom fiercely
If she does not admit to the groom and come back to him, but holds on to her iniquity
her thigh (indication of faithfulness) will waste away - and she will bear no children

so then with the children of God that our Groom years jealously over

but then in Numbers 6 - comes the 'true Bride'
the one with long hair
who will not drink of another spirit (also cf. 1 Tim 3:8)
- the one utterly dedicated/consecrated to the one He follows and submits to

He then will cause this:
Numbers 6:23-27 23 "Speak to Aaron and his sons, saying, Thus you shall bless the people of Israel: you shall say to them, 24 The LORD bless you and keep you; 25 the LORD make his face to shine upon you and be gracious to you; 26 the LORD lift up his countenance upon you and give you peace. 27 "So shall they put my name upon the people of Israel, and I will bless them."

His name will be put upon the unfaithful bride of Israel, and they will be blessed in Him, the Lord will shine the in the face of Jesus, His marvelous grace

So then knowing this salvation, let us no longer grieve the Spirit of jealousy who dwells within us, since the atoning sacrifice has been made, restitution has been given 120% - and we are all pronounced 'clean' and invited into the camp