In order to understand what it means to be saved, we need to understand that from which we need to be saved. The Bible teaches that because all men have sinned, they have fallen short of God's glory (Romans 3:23). It is these sins that separate us from God (Isaiah 59:2) putting us into a state of needing to be reconciled with God. Moreover, since God is a completely holy and righteous God, those who die in sins must be punished for the evil that they have done. What kind of punishment does one receive for offending an infinite God? The Bible teaches that those who die in a state of sin will receive eternal separation from God in hell (Matthew 25:46). Sinful man is doomed to condemnation. This is that from which men need salvation. What is man to do? As Paul asks, "Wretched man that I am, who shall deliver (i.e. save) me from this body of death?" (Romans 7:24)
Fortunately for man, God wants man to be saved from such an awful fate. That is the salvation that God offers; reconciliation with him through Jesus Christ (Romans 7:25, 2 Corinthians 5:18-21). Salvation is the opportunity to not have to be punished for the sins that we have committed. God has offered us an alternative. If we will believe that Jesus is God's Son, that Jesus came to the earth to provide something for man that man could not provide for himself, namely, salvation from sin, then God will allow Jesus' sacrificial death on the cross to be our vicarious punishment for our sins (2 Corinthians 5:21).
When we become saved by hearing God's word (Romans 10:17), believing it (Hebrews 11:6), repenting of sin (Acts 17:30), confessing Jesus as Christ (Matthew 10:32) and being baptized for the remission of sins (Acts 2:38, Acts 22:16), then we are born again into the family of God (John 3:3,5) and we become children of God (1 John 3:1) and heirs according to God's promise (Galatians 3:29). This entails that we can then call upon God as our Father and he considers us as His children (Galatians 4:6).
Now, while this is the basic story of salvation, the scriptures reveal to us that there are several perspectives of salvation. There is salvation at the moment of baptism. In this perspective, we gain a right relationship with God and we become his child (see Galatians 3:27-29). Here we have forgiveness of our past sins and we are able to worship God acceptably. In this perspective of salvation, we have come out of a detrimental relationship with God and entered into a constructive relationship with God. God begins, at this point, to mold us into the kind of person He wants us to be through our obedience to His word and our growth as a child of God. 1 Peter 2:2ASV states, "As newborn babes, long for the spiritual milk which is without guile, that ye may grow thereby unto salvation." While the newborn babe in Christ is saved in that he is in a right relationship with God, he still needs to continue to grow unto salvation in order to remain saved and inherit eternal life.
There is also salvation from sin committed after baptism. In this perspective we see salvation from sin as ongoing. Once we become a Christian, the blood of Christ covers the sins that we commit and confess (1 John 1:7-10) and we remain in a state of God's grace as we continue to serve and love Him. It doesn't mean that God excuses our sins. It means that when we sin and turn to God with a broken heart in penitence for our sins, then God continues to forgive our sins based upon our having been cleansed by the blood (Acts 8:22).
This doesn't mean, however, that we can't abandon God and lose our inheritance (2 John 1:8). We can, like the prodigal son, rebel against our father and wander off into a strange land (Luke 15:11-32). If we die in such a state, then we will lose our inheritance and will not be part of the kingdom of God (Galatians 5:19-21, 1 Corinthians 6:9, 10). Jesus himself even warned us that there would be some who call him Lord, but would not enter into eternal life (Matthew 7:21). So God's promise of forgiveness to His children is conditional upon the grounds that we remain faithful to God and His will (Revelation 2:10). God's relationship to us is Father to child, but if the child rejects and abandons the Father, then there is no more sacrifice for sin (Hebrews 10:26). We are children of God, but we must walk as God's children (1 John 3:10, Ephesians 5:8-11). If we stop walking as God's children we will be disinherited.
Consider also 2 Corinthians 7:9, 10 which says, "Now I rejoice, not that ye were made sorry, but that ye sorrowed to repentance: for ye were made sorry after a godly manner, that ye might receive damage by us in nothing. For godly sorrow worketh repentance to salvation not to be repented of: but the sorrow of the world worketh death." Notice that godly sorrow works repentance to salvation. What kind of salvation is that? Didn't these Christians already have salvation? Why would they need to repent to salvation if they already had it? This passage indicates that even those who were once saved, can so sin as to need to repent to salvation again.
Finally, there is another sense of the word "salvation" that refers to being saved out of this life and into the next. Consider 2 Timothy 2:10. Paul is speaking to those who are saved, yet he says, "Therefore I endure all things for the elect's sakes, that they may also obtain the salvation which is in Christ Jesus with eternal glory." If they already had it, then why would they need to "obtain" it? He must be referring to salvation in the next life in heaven with God and Christ. Notice also 1 Peter 1:4, 5 "To an inheritance incorruptible, and undefiled, and that fadeth not away, reserved in heaven for you, Who are kept by the power of God through faith unto salvation ready to be revealed in the last time." Again, this "salvation" is that which has not yet been "revealed" until, that is, the last time. That's heaven itself. So while a man may be saved in that he is currently in a right relationship with God, and also that he has ongoing forgiveness of sins, it is also the case that he has not yet obtained final salvation in heaven. That blessing is reserved for those who endure to the end (2 Timothy 4:8).
What does it mean to be saved? It means that the Christian has been taken out of darkness and into light, forgiven of his past sins, and become a child of God. It means that the Christian may now call upon God as Father and ask for ongoing forgiveness of sins committed after baptism, but it doesn't mean that the Christian can't abandon that relationship and return to darkness. And finally, it means that the Christian has God's promise that one day he will be saved from the sorrows, pains, and temptations of this life into a place where no evil shall dwell and Father and child may be together throughout eternity. Now, don't you want to be saved?