Numbers 5:14-15

14and if a feeling of jealousy comes over her husband and he suspects his wife who has defiled herself—or if a feeling of jealousy comes over him and he suspects her even though she has not defiled herself— 15then he is to bring his wife to the priest.

He must also bring for her an offering of a tenth of an ephah of barley flour.1 He is not to pour oil over it or put frankincense on it, because it is a grain offering for jealousy, an offering of memorial as a reminder of iniquity.