There have been false teachers since Eve sinned. I would consider Esau the first one, since he tried to get his brother to agree with his sacrifice and when Abel refused to agree with him, he slew him and buried him. God put a mark on Esau and he was a marked man from then on. And from then on there have always been false teachers. A lot of false teachers do it for money, some do it to draw men after them, others do it to feed their ego. There are lots of reasons, but the Bible is the only true and honest guide we can go by so when you hear a sermon, be like the Bereans, go home and study it out and make sure it was truth. There will be no false anything in heaven. Everything will be pure and honest.
Romans 16:17,18 "NowI beseech you brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them. For they that are such serve not our Lord Jesus Christ, but their own belly; and by good words and fair speeches deceive the hearts of the simple." This verse is right to the point and no need to misunderstand it.
Acts 20:30 "Also from among yourselves men will rise up speaking perverse things, to draw away disciples after themselves."
Ephesians 4:14 "We should no longer be children tossed to and fro and carried about with every wind of doctrine by the trickery of men, in the cunning craftiness of deceitful plotting."
1 Timothy 4:1,2 "Now the Spirit expressly says that in latter times some will depart from the faith, and giving heed to deceiving spirits and doctrines of demons, speaking lies in hypocrisy, having their own conscience seared with a hot iron."
Titus 1:10,11 "For there are many insubordinate, both idle talkers and deceivers, especially of the circumcision, whose mouths must be stopped, who subvert whole households, teaching things which they ought not, for the sake of dishonest gain. Could that be talking about money, giving their tithe and offerings to them. That happens a lot.
2 Peter 2:1-3 "But there were also false prophets among the people, even as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Lord who bought them, and bring on themselves swift destruction. And many will follow their destructive ways, because of whom the way of truth will be blasphemed. By coveteousness they will exploit you with deceptive words; for a long time their judgment has not been idle, and their destruction does not slumber."
Satan has his workers and he knows all about deceit and lies and how to turn us from truth to fables. We must be students of the word and give diligence to God's word. It is a matter of life and death, or living forever and dying and never living again. I want to live forever with my Savior, don't you. Let's not let anything or anybody come between us and our God. Take the Bible just as it reads and don't add any words to it or don't take any words out of it. Then we will be safe from Satan's tactics.