"Everything that I command you, you shall be careful to do. You shall not add to it or take from it.
If a prophet or a dreamer of dreams arises among you and gives you a sign or a wonder,
and the sign or wonder that he tells you comes to pass, and if he says, 'Let us go after other gods,' which you have not known, 'and let us serve them,'
you shall not listen to the words of that prophet or that dreamer of dreams. For the LORD your God is testing you, to know whether you love the LORD your God with all your heart and with all your soul." (Deuteronomy 12:32-13:3)

"Every word of God proves true; he is a shield to those who take refuge in him.
Do not add to his words, lest he rebuke you and you be found a liar."
(Proverbs 30:5-6)

"For God commanded, 'Honor your father and your mother,' and, 'Whoever reviles father or mother must surely die.'
But you say, 'If anyone tells his father or his mother, 'What you would have gained from me is given to God,'
he need not honor his father.' So for the sake of your tradition you have made void the word of God.
You hypocrites! Well did Isaiah prophesy of you, when he said:
'This people honors me with their lips, but their heart is far from me;
in vain do they worship me, teaching as doctrines the commandments of men.'" (Matt. 15:4-9)

"Then Jesus said to the crowds and to his disciples,
'The scribes and the Pharisees sit on Moses' seat,
so do and observe whatever they tell you, but not the works they do. For they preach, but do not practice.'" (Matt. 23:1-3)