With heads lifted up, not pressed down with a yoke. It notes their liberty, security, confidence, and glory. See Exodus 14:8 Numbers 33:3.
Related Commentaries of Leviticus 26:13
Leviticus 26:13
13 I am the LORD your God, which brought you forth out of the land of Egypt, that ye should not be their bondmen; and I have broken the bands of your yoke, and made you go upright.