“They went out from us, but they did not belong to us; for if they had belonged to us, they would have remained with us. However, they went out so that it might be made clear that none of them belongs to us.” ‭‭1 John‬ ‭2:19‬ ‭HCSB‬‬

They are antichrists who do not believe in Christ. They often tried to infiltrated churches to bring the church's theology into the same beliefs as their own. These antichrists are just people motivated by the devil to disrupt the unity of the Church and the gospel. But the churches John is writing to had the Holy Spirit operating in it and these antichrists could not disrupt the move and power of the Holy Spirit. so they moved on because they did not belong. 

All too often the devil does not change his attack plan, but we all too often forget how he tried to attack the church for the past 2,000 years and we fall victim to his attacks once again. There are churches and whole denominations who have allowed the devil to move into their midst and all the while pushing out the Holy Spirit, and Jesus. The devil does not come into a church or home looking like a mad red demon with a pitchfork, but he looks and talks and acts like a Christian but he preaches a gospel of inclusion rather than a gospel of conformation to God’s will. 

“For if a person comes and preaches another Jesus, whom we did not preach, or you receive a different spirit, which you had not received, or a different gospel, which you had not accepted, you put up with it splendidly!”

‭‭2 Corinthians‬ ‭11:4‬ ‭HCSB‬‬

https://www.bible.com/72/2co.11.4.hcsb

“I am amazed that you are so quickly turning away from Him who called you by the grace of Christ and are turning to a different gospel — not that there is another gospel, but there are some who are troubling you and want to change the good news about the Messiah. But even if we or an angel from heaven should preach to you a gospel other than what we have preached to you, a curse be on him! As we have said before, I now say again: If anyone preaches to you a gospel contrary to what you received, a curse be on him!”

‭‭Galatians‬ ‭1:6-9‬ ‭HCSB‬‬

https://www.bible.com/72/gal.1.6-9.hcsb

“But the Jews incited the prominent women, who worshiped God, and the leading men of the city. They stirred up persecution against Paul and Barnabas and expelled them from their district.”

‭‭Acts‬ ‭13:50‬ ‭HCSB‬‬

https://www.bible.com/72/act.13.50.hcsb

“The same thing happened in Iconium; they entered the Jewish synagogue and spoke in such a way that a great number of both Jews and Greeks believed. But the Jews who refused to believe stirred up and poisoned the minds of the Gentiles against the brothers.”

‭‭Acts‬ ‭14:1-2‬ ‭HCSB‬‬

https://www.bible.com/72/act.14.1-2.hcsb

The Devil is a copycat. He sees what God is doing and imitates it. But God is a creator He is always creating something new while keeping the message, and gospel the same. If we were to look into the miracles that were done in the Bible we would see that no miracle was done twice the same way. 

Take Moses, when the Israelites were wandering in the desert and needed water, God told Moses to strike the rock, but the next time God told Moes to speak to the rock, but instead, He struck it twice and was not able to enter the promise land. 

Look at all the times Jesus open a blind person’s eyes. One time Jesus put mud on the man's eye. one time He just laid his hands on him. Another time He put spit on the man’s eyes and had to touch him again to fully cure him. 

Look at the times people had to cross the water. At the Red Sea God caused a stiff wind to blow all night to divide the water. At the Jordan river as soon as the priests' feet touched the water the water was held back like a wall. Elijah and Elisha struck the water with the same mantle and it parted instantly. 

If we feel we are stuck in a copycat church we ought to make sure they are serving a creative God and not a copycat devil. If we are listening to any pastor we ought to be studying our Bible to make sure what they are teaching us is from God and not some deceptive words that sound right. 

“The people here were more open-minded than those in Thessalonica, since they welcomed the message with eagerness and examined the Scriptures daily to see if these things were so.”

‭‭Acts‬ ‭17:11‬ ‭HCSB‬‬

https://www.bible.com/72/act.17.11.hcsb

Don’t take my or any other person’s word for it study the Bible for yourself and let God speak the truth to you. 

“I did not send these prophets, yet they ran with a message. I did not speak to them, yet they prophesied. If they had really stood in My council, they would have enabled My people to hear My words and would have turned them back from their evil ways and their evil deeds. “Am I a God who is only near” — this is the Lord’s declaration — “and not a God who is far away?”

‭‭Jeremiah‬ ‭23:21-23‬ ‭HCSB‬‬

https://www.bible.com/72/jer.23.21-23.hcsb

“Call to Me and I will answer you and tell you great and incomprehensible things you do not know.”

‭‭Jeremiah‬ ‭33:3‬ ‭HCSB‬‬

https://www.bible.com/72/jer.33.3.hcsb

“For I know the plans I have for you” — this is the Lord’s declaration — “plans for your welfare, not for disaster, to give you a future and a hope. You will call to Me and come and pray to Me, and I will listen to you. You will seek Me and find Me when you search for Me with all your heart. I will be found by you” — this is the Lord’s declaration — “and I will restore your fortunes and gather you from all the nations and places where I banished you” — this is the Lord’s declaration. “I will restore you to the place I deported you from.”

‭‭Jeremiah‬ ‭29:11-14‬ ‭HCSB‬‬

https://www.bible.com/72/jer.29.11-14.hcsb