Hosea 10:4

‘They speak but words,

Swearing falsely in making covenants,

Therefore judgment springs up as poisonous weeds

In the furrows of the field.'

Hosea points out the folly of their words. They should recognise that they are but words, bold, brash, and foolish. For while they may still be swearing covenants, it is with gods who are unable to respond. They are false covenants. They are trusting in shadows. And that is why even now judgment is inevitably springing up around them, in the same way as poisonous weeds will inevitably spring up in the furrows of their fields, the aftermath of the abundant fruitfulness. The one is as inevitable as the other. And the Baal who does not prevent the hemlock, cannot prevent the judgment.

Alternately the false covenants may be those made with allies, or with Assyria itself. It would be their failure to observe the latter that would bring down on them what is threatened in Hosea 10:5.