Matthew 7:21(KJV): Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. 
22: Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?
23: And then will I profess unto them, I never knew you: depart from me, ye that work iniquity. 
What a sad day it will be for those who thought they did great things for God to not be allowed into heaven.

So what made these people miss the boat?  The answer is because they trusted in themselves that they were righteous and just tagged the name of Jesus on to it to make themselves appear as great Christians, when in fact they were not even Christians at all as Jesus stated in Matthew 7:23(KJV), "I never knew you: depart from me, ye that work iniquity." They thought they did many wonderful works, but the bible tells us the only work of God that gives eternal life is to believe on his only begotten Son.
John 6:28(KJV): Then said they unto him, What shall we do, that we might work the works of God?
John 6:29(KJV): Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent.  That is the only work we can do to get us into heaven, just believe on Jesus alone and nothing else.  All the work done to give us salvation was done by Jesus two thousand years ago when he died on the cross and rose from the grave as payment for our sins.. It is not what we do for Jesus that saves us, it is what he did for us that saves us.

In the book of Luke is a story of a man who thought he was righteous, but he actually was not.
Luke 18:9(KJV): And he spake this parable unto certain which trusted in themselves that they were righteous, and despised others
10: Two men went up into the temple to pray; the one a Pharisee, and the other a publican.
11: The Pharisee stood and prayed thus with himself, God, I thank thee, that I am not as other men are, extortioners, unjust, adulterers or even as this publican.
12: I fast twice in the week, I give tithes of all that I possess.
13: And the publican, standing afar off, would not lift up so much as his eyes unto heaven, but smote upon his breast, saying, God be merciful to me a sinner.
14: I tell you, this man went down to his house justified rather than the other; for every one that exalteth himself shall be abased; and he that humbleth himself shall be exalted.

It is simply by pure mercy that God saves us through trusting in the shed blood of Jesus Christ. We don't deserve salvation and we cannot earn it; it is a totally free gift . Titus 3:5(KJV): Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost.
Ephesians 2:8(KJV): For by grace are ye saved through faith; and that not of yourselves: it is the  gift of God. 9: Not of works, lest any man should boast.

The bible says that our own righteousness, or in other words, our own good works that we do that we think will get us into heaven, are in fact filthy rags to God.
Isaiah 64:6(KJV): But we are all as an unclean thing, and all our righteousnessess are as filthy rags; and we all do fade as a leaf; and our iniquities, like the wind, have taken us away.

Therefore, in conclusion, if you are trusting in your own works that you are doing in the name of religion or in the name of Christ, you are not saved, but if you have put your trust only in Jesus for your salvation and what he did for you, when he died on the cross and rose again the third day, you are saved. You are either trusting in your own self, or you are trusting totally on Jesus for your salvation, and the bible says in John 14:6(KJV): Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.

John 3:36(KJV): He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life; but the wrath of God abideth on him. Notice how this verse says "he that believeth", not he that does great and wonderful works.  It is not about what we do for Jesus, it is about what Jesus did for us.  When you decide to put your trust in Jesus and not yourself for salvation, that is called receiving Jesus as your personal savior.  John 1:12(KJV): But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name.  So the way to receive him as your own savior is to simply believe on his name, trust him to forgive your sins and give you eternal life, and have absolutely no trust in yourself or anything that you could ever do.  When you do that you become God's child, as it says 'he gave them power to become the sons of God."  The bible also says to call upon him when you are putting your trust and faith in him.  To put your trust in Jesus just call upon him to save you and he will. Romans 10:9(KJV): That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.  Romans 10:13(KJV): For whosoever shall call upon the name of the Lord shall be saved. 

God's Simple Plan of Salvation

The Bible Way To Heaven