'Back' in the Bible

The one who scatters has come up against you.Man the fortress, watch the road;Strengthen your back, summon all your strength.

For turned back hath Jehovah to the excellency of Jacob, As to the excellency of Israel, For emptied them out have emptiers, And their branches they have marred.

The chariots dash madly through the streets;they rush around in the plazas.They look like torches;they dart back and forth like lightning.

But Nineveh is of old like a pool of water: yet they shall flee away. Stand, stand, shall they cry; but none shall look back.