Jamieson, Fausset & Brown

Strengthen . . . hands . . . confirm . . . knees--The Hebrew for "strengthen" refers to the strength residing in the hand for grasping and holding a thing manfully; "confirm," to the firmness with which one keeps his ground, so as not to be dislodged by any other [MAURER]. Encourage the Jews, now desponding, by the assurance of the blessings promised.