passage in Mark is one in which divorce proceedings may be instituted by the woman as well as by the man. There can be no doubt then that our Lord here enunciates a law or principle which applies to a situation in which divorce by the woman as well as by the man is recognized as belonging to the actual status quo.… This verse points in the direction of a distinct provision in the Christian economy to the effect that the woman is accorded an equal right with the man in the event of marital unfaithfulness