NOT ALL WHO PROFESS TO BE CHRISTIANS ARE TRUE CHRISTIANS
Not all who claim to be true Christians or who think they are saved and headed for heaven, truly are, according to the Bible. Another term often used for that kind are "Professing Christians."
*The sheep and goats parable - Matthew 25. It shows how many on Judgment Day, who assumed they were Christians, will find that God sees them as not being true Christians. And it tells how all those who are found to be not true Christians - will be thrown into hell.
*Think of the Jews of Jesus' time, who knew only Judaism. They thought they were headed for heaven. And they were well acquainted with the scriptures - especially Bible scholars and officials in the temple and tabernacles in Jesus' time.
John 8:42
42 Jesus said unto them, If God were your Father, ye would love me: for I proceeded forth and came from God; neither came I of myself, but he sent me.
KJV
Comment: Jesus was telling the Jews who were listening to HIm in this passage, that their "Father" was the devil, and not the one and only true God there is, which the BIble tells about. This is because though they knew the scriptures well, and were very religious in various ways - they still were not acceptable to God, because they had refused to accept Jesus and His teachings.
Luke 13:4-5
4 Or those eighteen, upon whom the tower in Siloam fell, and slew them, think ye that they were sinners above all men that dwelt in Jerusalem?
5 I tell you, Nay: but, except ye repent, ye shall all likewise perish.
KJV
Comment: Jesus was explaining to these religious Jews, who were followers of Judaism, that unless they truly repented of their sins, and received forgiveness of their sins through Jesus - that they would end up in hell if they weren't willing to do those things to make sure they were acceptable and pleasing to God.
Matt 7:14-16
14 Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.
15 Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.
16 Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?
KJV
Comment: In this passage, Jesus made it plain that far greater numbers of people, throughout history, miss the narrow gate that leads to heaven. As compared to the smaller percentage who manage to get through the narrow gate that leads to heaven. So it isn't wise to be unconcerned about one's eternal destiny or to assume that one is headed for heaven, without making a thorough checkup on oneself to see just what the case is, with himself. And if one finds after examining oneself, that he is not yet headed for heaven - he needs to do what he can do, to make sure he does for sure (no doubts in mind about it) know he's truly destined for heaven after this life is over.
Heb 6:4-6
4 For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost,
5 And have tasted the good word of God, and the powers of the world to come,
6 If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.
KJV
Comment: This passage shows it is possible to fall away from Christ - to no longer be a child of God. This is not a helpless kind of falling away, as God never allows anyone to be helpless in that matter. II Peter 3:9. The only way to fall away - is through a person's choice to turn away from Christ. It is evident that some do fall away, since there wouldn't be this warning in the Bible if it was true that no Christians ever fell away from Christ. Also, they wouldn't be reminded to be careful not to fall away, if there was nothing they could do on their part, to prevent it from happening.
Gal 6:3
3 For if a man think himself to be something, when he is nothing, he deceiveth himself.
KJV
Comment: Assuming oneself to be anything is no certain proof that he is what he thinks he is. One needs to examine oneself carefully and prayerfully, in the light of God's Word, in order to reveal to himself whether his life is satisfactory to God or not. II Corinthians 13:5
James 1:23-25
23 For if any be a hearer of the word, and not a doer, he is like unto a man beholding his natural face in a glass:
24 For he beholdeth himself, and goeth his way, and straightway forgetteth what manner of man he was.
25 But whoso looketh into the perfect law of liberty, and continueth therein, he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his deed.
KJV
Comment: Many know God's Word, but do not wholeheartedly put it to practice in their lives. James knew this, I'm sure, as he wouldn't have mentioned this otherwise.
Matt 5:20
20 For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.
KJV
Comment: Jesus said that the degree of righteousness of the scribes and Pharisees wasn't enough to get them into heaven. It's true that under Judaism, they followed some very strict religious laws. But that wasn't enough to save them, alone, according to Jesus.