In that He said, "Rejoice, thou barren that bearest not," He referred to us, for our Church was barren before that children were given to her. But when He said, "Cry out, thou that travailest not," He means this, that we should sincerely offer up our prayers to God, and should not, like women in travail, show signs of weakness.  And in that He said, "For she that is desolate hath many more children than she that hath an husband," He means that  our people seemed to be outcast from God, but now, through believing, have become more numerous than those who are reckoned to possess God.  And another Scripture saith, "I came not to call the righteous, but sinners."  This means that those who are perishing must be saved. For it is indeed a great and admirable thing to establish, not the things which are standing, but these that are falling. Thus also did Christ desire  to save the things which were perishing,  and has saved many by coming and calling us when hastening to destruction.