'That annulled,' or 'done away,' may appear a little harsh, but the apostle uses it as a formula for the old covenant done away in Christ. If this be borne in mind, the sense will be clearer by the use of it. It contrasts 'that annulled' with 'that which abides:' so vers. 13 and 14.
As 'hardened,' Mark 3.5; 'blinded,' Rom. 11.7.
I have no doubt that the text is right, and that Moses covered his face while he talked to the people, and that the Hebrew, Ex. 34.33, means nothing else, and ver. 34 proves it.