Can a believer's name be blotted out of the book of life?

We had an email question from a reader which asked about whether or not our names can be blotted out of the lamb's book of life. Below is the question and our response.

"I am a believer (has accepted Christ). I used to believe as you that once saved always saved. And I think I still DO believe that. However, recently, a man a work who belongs to Assembly of God church tells me that we can lose our salvation and have our names blotted out of the lambs book of life. He says that if you are back-slidden and don' repent you will NOT go to heaven, and that you WILL LOSE your salvation. He states Revelation 17:8 and Revelation 3:5 pertaining to "those blotted out" are believers, otherwise their names would not have been written in the book. Please decipher this message for me. Now, all of a sudden, I feel that I have lost the joy of my salvation and am extremely worried that sins I have committed or am going to will make me lose salvation"
I am not sure what he is trying to do with those verses, but they do not say that anyone has ever had their name blotted out of the book of life. In fact, they say just the opposite, that no believer will ever be blotted out.

Rev 3:5 He who overcomes will, like them, be dressed in white. I will never blot out his name from the book of life , but will acknowledge his name before my Father and his angels.

Rev 17:8 The beast, which you saw, once was, now is not, and will come up out of the Abyss and go to his destruction. The inhabitants of the earth whose names have not been written in the book of life from the creation of the world will be astonished when they see the beast, because he once was, now is not, and yet will come.

They have either never been written in it or were promised to never have it removed. Other Scriptures say it the same way.

Rev 13:8 all whose names have not been written in the book of life belonging to the Lamb that was slain from the creation of the world.

Rev 20:15 If anyone's name was not found written in the book of life , he was thrown into the lake of fire.

Rev 21:27 Nothing impure will ever enter it, nor will anyone who does what is shameful or deceitful, but only those whose names are written in the Lamb's book of life . NIV

God promised to never blot out the names of those who are saved and Rev 17:8 says those who go into the abyss had never had their names written in it to begin with, not that their names were in but later blotted out.

They might be trying to make the word "overcome" sound as if it means that we must "work" to overcome and keep our names in the book of life. However, we know from Scripture that is not true. Who is it that overcomes? He who works for it? No. The Scripture tells us plainly.

1 John 5:5 Who is it that overcomes the world? Only he who believes that Jesus is the Son of God.

That is how we overcome, we believe. And if we overcome, which means if we believe that Jesus is the Son of God, then we will never have our names blotted out of the book of life.

As we can see, it is essential that we test all of mans teaching against the Scripture. The exact Scripture they were using to make their point actually contradicted it. Never take any man's word for it, but go to the Word of God and read it, in it's entire context. If it contradicts what they are teaching then what they are teaching is wrong. It's that simple.