John Gill Bible Commentary

My flesh and my skin hath he made old,.... His flesh with blows, and his skin with smiting, as the Targum; his flesh was so emaciated, and his skin so withered and wrinkled, that he looked like an old man; as our Lord, when little more than thirty years of age, what with his sorrows and troubles, looked like one about fifty: he hath broken my bones; that is, his strength was greatly weakened, which lay in his bones; and he could not stir to help himself, any more than a man whose bones are broken; and was in as much pain and distress as if this had been his case; otherwise it was not literally true, either of the Jews, or of Jeremiah, or of Christ.