From the Third Reading of Matins for today, the Sunday After Ascension, taken from 1 John 2: 3, 4.
"And by this we know that we have known him, if we keep his commandments. He who saith that he knoweth him, and keepeth not his commandments, is a liar, and the truth is not in him."
True for all, especially for popes, prelates and presbyters.