I know that we are saved by grace and by faith, and that faith without works is dead. I'm confused though, it seems like salvation is just based on chance, whether God chooses you or not. I don't see a way to differentiate between which sinners get saved and which don't. If we're all sinners, why not everybody be saved?
If you're not confused, you're not alone. At this discussion board you can read a broad range of things that are claimed to save you, such as...
1. Water baptism.
2. Following the Law (then there will be an argument over what is meant by the Law)
3. Church membership, or you'll be saved by joining the right church with the right doctrine. Many claim to be THE CHURCH and others are false.
4. Following a five-step salvation process of hearing, believing, confessing, repenting and being baptized in water.
5. There is one salvation for Gentiles and another for Jews. Gentiles will spend eternity one place and Jews/Israel will be somewhere else.
6. Faithfulness to the assembly and abstaining from instrumental music in worship, giving your offerings on Sunday mornings only, worshipping on Sunday mornings only, taking communion every Sunday and from one cup.
7. Worshipping on the Sabbath, which is still Saturday.
8. Abstaining from worldly things like makeup and jewelry (this is legalism).
9. Being baptized in the Holy Spirit with the evidence of speaking in other tongues.
This is a short list but these are those things that first came to my mind.
Here's the Gospel summarized in one Chapter.
Rom 5:1 Therefore, having been justified by faith, we have peace with God through our Lord Jesus Christ,
Rom 5:2 through whom also we have obtained our introduction by faith into this grace in which we stand; and we exult in hope of the glory of God.
Rom 5:3 And not only this, but we also exult in our tribulations, knowing that tribulation brings about perseverance;
Rom 5:4 and perseverance, proven character; and proven character, hope;
Rom 5:5 and hope does not disappoint, because the love of God has been poured out within our hearts through the Holy Spirit who was given to us.
Rom 5:6 For while we were still helpless, at the right time Christ died for the ungodly.
Rom 5:7 For one will hardly die for a righteous man; though perhaps for the good man someone would dare even to die.
Rom 5:8 But God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us.
Rom 5:9 Much more then, having now been justified by His blood, we shall be saved from the wrath of God through Him.
Rom 5:10 For if while we were enemies we were reconciled to God through the death of His Son, much more, having been reconciled, we shall be saved by His life.
Rom 5:11 And not only this, but we also exult in God through our Lord Jesus Christ, through whom we have now received the reconciliation.
Rom 5:12 Therefore, just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned--
Rom 5:13 for until the Law sin was in the world, but sin is not imputed when there is no law.
Rom 5:14 Nevertheless death reigned from Adam until Moses, even over those who had not sinned in the likeness of the offense of Adam, who is a type of Him who was to come.
Rom 5:15 But the free gift is not like the transgression. For if by the transgression of the one the many died, much more did the grace of God and the gift by the grace of the one Man, Jesus Christ, abound to the many.
Rom 5:16 The gift is not like that which came through the one who sinned; for on the one hand the judgment arose from one transgression resulting in condemnation, but on the other hand the free gift arose from many transgressions resulting in justification.
Rom 5:17 For if by the transgression of the one, death reigned through the one, much more those who receive the abundance of grace and of the gift of righteousness will reign in life through the One, Jesus Christ.
Rom 5:18 So then as through one transgression there resulted condemnation to all men, even so through one act of righteousness there resulted justification of life to all men.
Rom 5:19 For as through the one man's disobedience the many were made sinners, even so through the obedience of the One the many will be made righteous.
Rom 5:20 The Law came in so that the transgression would increase; but where sin increased, grace abounded all the more,
Rom 5:21 so that, as sin reigned in death, even so grace would reign through righteousness to eternal life through Jesus Christ our Lord.
The one man's disobedience refers to Original Sin, which came from Adam's disobedience to what God had told Him. God did not forsake him and in fact God sought out Adam and called to Him. There was a penalty for his sin - he and Eve became aware of sin and this were guilty of sin, but God was still gracious to them. This sin was called "original sin" because this was the first act of man's rebellion against God. Mankind and the world have been cursed sin.
One man's obedience refers to Christ's obedience to completing His mission on this Earth and becoming the perfect blood sacrifice on the cross which has since reconciled all of mankind back to God. However, not all have faith, and this is where faith comes in. It has been offered to all but not all will accept it and still reject God's Grace and believe that they are righteous by their own works. Many atheists will claim that they live moral lives, sometimes more moral than Christians, but that will not help them. God Almighty sees us by the Blood of Christ. Christ is our Mediator, and our Great High Priest in Heaven.
Christ took all of mankind's sins upon Himself at the cross. This sin and the required payment for sin were nailed to the cross. The Law requires a payment but Grace makes the provision. He was and is our provision. The Father sees us as forgiven by the Blood of Christ. Don't let anyone tell you otherwise as there is nothing else in existence that is effective against the sin nature of mankind.
One day we will all be with Him and we will have eternal glorified bodies and will no longer be in these temporary shells we call flesh. The flesh will decay and it will die and then decay even more. We can't clean up these dead bodies - only our faith in Christ can give us the life we need to live with Him for eternity.
Also, we are not like the Jews. We are not bound by the Torah (the first five books of the Old Testament). That was their teacher. We have a new Teacher and His name is The Holy Spirit.
Rom 8:12 So then, brethren, we are under obligation, not to the flesh, to live according to the flesh--
Rom 8:13 for if you are living according to the flesh, you must die; but if by the Spirit you are putting to death the deeds of the body, you will live.
Rom 8:14 For all who are being led by the Spirit of God, these are sons of God. 
