'Backs' in the Bible

The Israelis have been unable to stand before their enemies. They're turning their backs and running from their enemies because they themselves have been turned over to destruction. I will not be with you anymore unless you destroy these things that have been turned over to destruction.

know for certain that the LORD your God will not continue to drive out these nations ahead of you. Instead, they will be a snare and a trap for you, a whip to your backs, and thorns in your eyes, until you perish from this good land that the LORD your God has given you.