righteousness which is of faith speaketh on this wise - “speaketh thus” - its language or import is to this effect (quoting in substance Deu 30:13, Deu 30:14).
Say not in thine heart, Who shall ascend into heaven? that is, to bring Christ down, etc. - that is, “Ye have not to sigh over the impossibility of attaining to justification; as if one should say, oh! if I could but get someone to mount up to heaven and fetch me down Christ, there might be some hope, but since that cannot be, mine is a desperate case.”