'Weak' in the Bible

So the previous command is annulled because it was weak and unprofitable

For the law appoints as high priests men who are weak, but the promise of the oath, which came after the law, appoints a Son, who has been perfected forever.

quenched the raging of fire, escaped the edge of the sword, gained strength after being weak, became mighty in battle, and put foreign armies to flight.

Therefore, strengthen your tired arms and your weak knees,