‘O Ephraim, what shall I do to you?
O Judah, what shall I do to you?
For your covenant love is as a morning cloud,
And as the dew which goes early away.'
We can see in this the cry of a father's heart for his children (compare Hosea 11:1; Hosea 11:4; Exodus 4:22; Deuteronomy 14:1; Isaiah 63:16; Isaiah 64:8). God is, as it were, in despair at what to do with them because He loves them so much whilst they are unwilling to listen to what He says. He feels that He has tried everything. We can see those attempts for ourselves, starting from the deliverance from slavery in Egypt, moving through the conquest and the deliverances under the Judges, and coming to Samuel, David, Solomon and the prophets, and the ups and downs which followed, before finally attaining the prosperous times under Uzziah and Jeremiah II, followed by the threat of the Assyrians. During that past they have again and again professed covenant love (obedience and response to the covenant in loving worship), but sadly it has always proved to be like a morning mist and like the dew, which, when the sun arises, which rapidly evaporate and disappear. It has never lasted for any great length of time. The morning mist and dew were common sights in Israel, and provided vital moisture outside the rainy season, and all knew how quickly they dissolved before the morning sun.
So in contrast to the sure work which, once they had repented, YHWH would do as sure as morning came after night time (Hosea 6:3), where the morning was a picture of certainty, here the coming of morning is simply a picture of how quickly their love and faithfulness has disappeared. Furthermore, in contrast with the latter rains from God which would water the earth and make if fruitful (Hosea 6:3), the behaviour of Israel and Judah was like a rapidly disappearing morning mist.