The Man is To Bring His Wife to the Priest With An Offering of Memorial (Numbers 5:15).
“ Then shall the man bring his wife to the priest, and shall bring her oblation for her, the tenth part of an ephah of barley meal. He shall pour no oil on it, nor put frankincense on it, for it is a grain offering of jealousy, a grain offering of memorial, bringing iniquity to remembrance.”
The man must then bring his wife to the priest. We must see it as very likely that the priest, probably experienced in such things, would discuss the matter before acting in order to discover what grounds there were for the suspicion. He would not want to be involved in something which just arose from a family quarrel, a case that might soon be dropped. The task he was being asked to perform was a sacred one. Serious questions would be asked.
But once he was convinced that there may be genuine grounds for suspicion the husband would then have to present him with a grain offering. This was not a worship offering, for no oil (signifying blessedness) or frankincense (signifying worship) was to be included. It was of a similar nature to the individual sin offering for a poor person (Leviticus 5:11). But it was even lower than that for the grain here was to be the cheapest of grains, the tenth part of an ephah of barley meal. Barley was cheap (2 Kings 7:1), the food for the poor and for animals.
It was ‘a grain offering of jealousy', that is a representation before Yahweh of his sense that he had been betrayed and that Yahweh had been betrayed and that his wife had sinned wickedly and had defiled the camp. But the aim was not atonement. He was seeking righteousness and the removal of the defilement on the whole of Israel. The offering was to draw Yahweh's attention to the situation, bringing the supposed sin into remembrance (aware that Yahweh would already know about it), and assuring Him that they were concerned about it too. It was a ‘grain offering of memorial'.