Therefore, strengthen your feeble arms and weak knees. (NIV)
So then, brace up and reinvigorate and set right your slackened and weakened and drooping hands and strengthen your feeble and palsied and tottering knees, [Isa. 35:3.] (AMP)
Wherefore lift up the hands which hang down, and the feeble knees; (KJV)