Bible:
Revelation 22:19
18 I testify to everyone who hears the words of prophecy in this book: If anyone adds to them, God will add to him the plagues described in this book.
19 And if anyone takes away from the words of this book of prophecy, God will take away his share in the tree of life and the holy city, which are described in this book.
Deuteronomy 4:2
You must not add to or subtract from what I command you, so that you may keep the commandments of the LORD your God that I am giving you.
Deuteronomy 12:32
See that you do everything I command you; do not add to it or subtract from it.
Proverbs 30:6
Do not add to His words, lest He rebuke you and prove you a liar.
Luke 11:52
Woe unto you, lawyers! for ye have taken away the key of knowledge: ye entered not in yourselves, and them that were entering in ye hindered.
Quran:
Verse (5:13)
So for their breaking of the covenant We cursed them and made their hearts hard. They distort words from their [proper] usages and have forgotten a portion of that of which they were reminded. And you will still observe deceit among them, except a few of them. But pardon them and overlook [their misdeeds]. Indeed, Allah loves the doers of good.