Your words have supported those who stumbled; you have strengthened faltering knees.
OJBThy words have upheld him that was falling, and thou hast strengthened the feeble birkayim (knees).
RVThy words have upholden him that was falling, and thou hast confirmed the feeble knees.
T4TBy what you said, you have helped those who ◄needed spiritual help/almost quit trusting in God► [MET], and you have enabled them to become spiritually strong again [MET].