Pre-trib theory is extra-Biblical

It amazes me how pre-trib teachers/supporters do not fear in adding extra-Biblical teachings to what is really taught in Revelation and the rest of the Bible. They keep defying and rebelling against God and thereby invite God's wrath on themselves. Why are people so foolish? It's because they yield to Satan and his demons.

Revelation 22:18-19 (NLT):
"And I solemnly declare to everyone who hears the words of prophecy written in this book: If anyone adds anything to what is written here, God will add to that person the plagues described in this book. 19 And if anyone removes any of the words from this book of prophecy, God will remove that person’s share in the tree of life and in the holy city that are described in this book."

I believe the warning from vs. 19 can also be applied to when quoting verses like Romans 8:1 (in which people defiantly ignore and leave out the phrase "who walk not after the flesh, but after the Spirit").

Romans 8:1 (authorized KJV):
"There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit."

Deuteronomy 4:2 (authorized KJV):
"Ye shall not add unto the word which I command you, neither shall ye diminish ought from it, that ye may keep the commandments of the Lord your God which I command you."

Deuteronomy 4:2 (NLT):
"Do not add to or subtract from these commands I am giving you. Just obey the commands of the Lord your God that I am giving you."