en_tn_condensed/hos/05/07.md

They were unfaithful to Yahweh, for they have borne illegitimate children

Possible meanings are 1) this means the Israelites were marrying people from other nations and having children with them or 2) this means the Israelite parents were unfaithful to Yahweh and they were teaching their children to worship idols.

Now the new moon festivals will devour them with their fields

The people of Israel were supposed to celebrate during the new moon. Here this expression seems to describe the new moon festival as a beast that will eat the people and their fields. However, it is hard to interpret this expression; many versions translate it without making much sense of it. However, the overall meaning is certainly that God will punish the people for their unfaithfulness to him. (See: rc://en/ta/man/translate/figs-personification)