John Gill

Thus saith the Lord God unto these bones,.... By the prophet, who was sent to prophesy over them: behold, I will cause breath to enter into you, and ye shall live; and none could do this but the living God, who breathed the breath of life into Adam at first, and he became a living soul; to which there seems to be an allusion here; and when the Lord puts his Spirit into men, or bestows his grace on them, then they shall live, and not till then.