Jesus says in John chapter 6:
John 6:47
47 Verily, verily, I say unto you, He that believeth on me hath everlasting life.
According to Jesus Christ, anyone who believes in Him has - present tense, right now - everlasting life.
This article will explain why He made that promise, how it affects you, and how you can be sure that you will go to Heaven when you die, according to the Word of God.
The purpose of God giving us the Law (including the Ten Commandments) in the Old Testament was to show us our need for a savior:
Galatians 3:24
24 Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith.
No one has ever kept the Law, or come anywhere close to keeping it (Romans 3:10-12, Psalm 14:2-3, Ecclesiastes 7:20):
Romans 3:23
23 For all have sinned, and come short of the glory of God;
James 2:10
10 For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all.
As a result, no one can be justified before God by keeping the Law:
Romans 3:20
20 Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin.
Galatians 3:11
11 But that no man is justified by the law in the sight of God, it is evident: for, The just shall live by faith.
Keeping the Law requires avoiding any sin, as the Bible says, "sin is the transgression of the Law" (1 John 3:4). Keeping the Law also requires you to behave perfectly towards God and others (Matthew 22:37-40). Therefore, because all of these things are contained in the Law, you cannot get to Heaven by being a good person, or by avoiding being a bad person, since no one is justified by the Law in God's sight.
Jesus Christ, God in the flesh, prophesied to come for thousands of years in the Old Testament, kept the entire Law perfectly, even though He allowed himself to be tempted in a human body. In doing this, He fulfilled the Law (Matthew 5:17, Galatians 3:13).
Because Jesus was sinless, He was able to bear the sins of humanity. His substitutionary death, to redeem mankind, was the principle purpose in Him coming to earth (Hebrews 2:9).
On the cross, God placed every single sin that you've ever done or ever will do on Jesus Christ, and punished Him in your place, as prophesied in the Old Testament (Isaiah 53:5-12):
2 Corinthians 5:21
21 For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.
1 Peter 2:24
24 Who his own self bare our sins in his own body on the tree, that we, being dead to sins, should live unto righteousness: by whose stripes ye were healed.
After three days, as prophesied in the Old Testament (Jonah 1:17, Matthew 12:40), Jesus rose from the dead, showing that the payment for sins was complete.
Jesus Christ's payment for sin is the only payment that God accepts to meet your debt to the Law:
Hebrews 9:12, 22
12 Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us.
22 And almost all things are by the law purged with blood; and without shedding of blood is no remission.
The basis for our justification before God is only that payment - not our own personal righteousness. That is why none can be justified by keeping the Law. Good works do not atone for sin, only Christ's payment atones for sin.
In order to have Jesus Christ's payment for sin apply to you personally, God simply requires that you stop trusting in your own righteousness to justify you, and put your faith in Jesus Christ alone to save you from the penalty for your sins:
Acts 16:30-31
30 And brought them out, and said, Sirs, what must I do to be saved?
31 And they said, Believe on the Lord Jesus Christ, and thou shalt be saved, and thy house.
When the Bible says "saved" here, it is referring to being saved from the punishment for your sins, saved from Hell (Matthew 1:21, John 3:17). And what do you have to do to be saved? Put your faith in Jesus Christ, instead of yourself. It's a simple transfer of trust.
Any of your own good works are explicitly excluded as the basis for Salvation (Titus 3:5). This is why the atonement that Jesus Christ provides is described as a "gift" (Romans 5:15-18, 6:23, John 4:10):
Ephesians 2:8-9
8 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.
This is important, because it demonstrates that all of your faith has to be in Jesus Christ. Salvation from Hell is not a cooperative effort between you and Jesus. We are saved by the grace of God, to the exclusion of our own works:
Romans 11:6
6 And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then it is no more grace: otherwise work is no more work.
As can be seen above, Salvation is truly free, because its given by grace.
Putting your faith in Jesus Christ as your Savior ensures that you will go to Heaven when you die. All of your sins - past, present, and future - are paid for, and so you will never again come into condemnation before God:
John 5:24
24 Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life.
The article entitled Top Ten Verses Proving Eternal Security proves this doctrine many different ways from the Word of God. Salvation is permanent, and obtained at the moment of faith.
Very often, people who learn about the freeness of Salvation ask about whether the fact that we are guaranteed to go to Heaven when we die means that it's permissible to do evil things. Nowhere does the Bible teach that you should do evil things simply because Salvation is free.
So, what happens if a Christian decides to live a very wicked life, and what is the motivation to live righteously after Salvation?
The first motivation is to secure the blessing of God on our lives (Psalm 1:1-3), and also to avoid God's chastening here on this earth:
Hebrews 12:6
6 For whom the Lord loveth he chasteneth, and scourgeth every son whom he receiveth.
You're a child of God if you are saved (John 1:12, Galatians 3:26), and so God, as your Father, will discipline you if you misbehave, here on earth. There are many things that can happen to a sinning Christian in Scripture, including sickness and death (1 Corinthians 11:30-32), but going to Hell is never one of them.
The second motivation given to a Christian to live righteously is the fact that we will earn or lose eternal rewards in Heaven based on how we live on earth:
1 Corinthians 3:11-15
11 For other foundation can no man lay than that is laid, which is Jesus Christ.
12 Now if any man build upon this foundation gold, silver, precious stones, wood, hay, stubble;
13 Every man's work shall be made manifest: for the day shall declare it, because it shall be revealed by fire; and the fire shall try every man's work of what sort it is.
14 If any man's work abide which he hath built thereupon, he shall receive a reward.
15 If any man's work shall be burned, he shall suffer loss: but he himself shall be saved; yet so as by fire.
A Christian will be rewarded for the good things that they do. Notice that even if all of the Christian's works are burned up, they are still saved (verse 15).
There is an entire article dedicated to this topic of eternal rewards entitled The Bible's Teaching on Eternal Rewards, which I would recommend if you'd like more teaching on this doctrine.
In short, we behave after Salvation to please the God that loved us enough to die for us, to show our love for those who God has blessed us to be able to influence, to secure God's blessing on our lives, to avoid God's temporal punishments here on earth, and to earn eternal rewards in Heaven. This has nothing to do with Salvation, and threatening a believer with Hell is not something that God uses to "motivate" a Christian anywhere in the Bible, because such a thing is absurd and impossible.
All those who put their faith in Jesus Christ have Everlasting Life. I hope that this article has either helped you to do so, if you hadn't in the past, or strengthened your faith, if you already have.
If you have any questions, or if anything was unclear, please feel free to contact me at the About & Contact tab. May God guide you, and have a great day.