Ephraim feedeth on wind, and followeth after the east wind: he daily increaseth lies and desolation; and they do make a covenant with the Assyrians, and oil is carried into Egypt.
The Prophet here inveighs against the vain hopes of the people, for they were inflated with such arrogance, that they despised all instruction and all admonitions. It was therefore necessary, in the first place, to correct this vice, and hence he says, Ephraim feeds on wind For when one gulps the wind, he seems indeed to fill his mouth, and his throat, and his chest...
In these verses, I. Ephraim is convicted of folly, in staying himself upon Egypt and Assyria, when he was in straits (Hos 12:1): Ephraim feeds on wind, that is, feeds himself with vain hopes of assistance from man, when he is at variance with God; and, when he meets with disappointments, he still pursues the same game, and greedily pants and follows after the east...
Commenting on Hosea 12:1-6
Ephraim feedeth on wind,.... Which will be no more profitable and beneficial to him than wind is to a man that opens his mouth, and fills himself with it: the phrase is expressive of labour in vain, and of a man's getting nothing by all the pains he takes; the same with sowing the wind, and reaping the whirlwind, Hos 8:7; and so the Targum...