Mark Dever spoke on False Conversions — The Suicide of the Local Church:

Langston Hughes was a popular 20^th century American Author who recounted how he was saved, but not really saved:

I was saved from sin when I was going on 16, but not really saved.  There was a big revival going on in my Auntie Rita’s church.  Every night for weeks, there had been much preaching, praying, shouting.  Finally everyone had gone to the altar and been saved – except my friend and I. 

My friend’s name was named Westley.  Westley and I were surrounded by sisters and deacons praying. It was very hot in the church, and getting late now. Finally Westley said to me in a whisper: “I’m tired o’ sitting here. Let’s get up and be saved.” So he got up and was saved.

Then I was left all alone on the mourners’ bench. My aunt came and knelt at my knees and cried, while prayers and song swirled all around me in the little church. The whole congregation prayed for me alone, in a mighty wail of moans and voices.  And I kept waiting serenely for Jesus, waiting, waiting – but he didn’t come.  I wanted to see him, but nothing happened to me.  Nothing!  I wanted something to happen to me, but nothing happened. . .  God had not struck Westley dead for taking his name in vain or for lying in the temple.  So I decided that maybe to save further trouble, I’d better lie, too, and say that Jesus had come, and get up and be saved.

So I got up.

Suddenly the whole room broke into a sea of shouting, as they saw me rise.  Waves of rejoicing swept the place. Women leaped in the air.  I couldn’t bear to tell my Aunt that I had lied, that I’d deceived everybody in the church, that I hadn’t seen Jesus, and that now I didn’t believe there was a Jesus anymore.

False Conversions can come in all shapes and sizes.  Dever spoke about how in true conversion, sound doctrine will be accompanied by self sacrificial love:

Sound Doctrine is Good (Doctrines of Grace) – Dever: “Sound doctrine in a church is important.  But this may attract spiritual accountants and theological hobbyists who want nothing to do with the need to love one another. 

We have readers in our church — guys who love to read the Puritans, but won’t get up an hour early to help a 90-year-old man get to church.  To such I’ve said: ‘Perhaps you’re not a Christian.’  Demons are great theologians.  Demons could ace any class at Southern Seminary, getting a better grade than all of us.

And one more:

False teaching makes false converts.  And false converts hire false teachers.  There is a symbiotic relationship between false converts and false teachers.  Think of what this does to the future of your congregation.  If you want to make sure your successor doesn’t preach the gospel, just add false converts to your church.