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. -1John 2: 3-4
Along these lines, we also read in Matthew 7: 13-15:
Enter ye in at the narrow gate: for wide is the gate, and broad is the way that leadeth to destruction, and many there are who go in thereat. How narrow is the gate, and strait is the way that leadeth to life: and few there are that find it! Beware of false prophets, who come to you in the clothing of sheep, but inwardly they are ravening wolves.Our Lord has strong words for those who purport to lead His sheep in the way of truth, but instead lead them in the way of destruction! May we always heed the words of Our Lord, Jesus Christ and the teachings of His Holy Church and beware those who would lead us astray!