Please explain the concept of being a sinner to me and why we are deemed evil and unworthy and in need of a saviour, I don't understand this concept.
I haven't read the responses others have posted yet, so I'm answering based solely upon your question here.
The word "sin" comes from Old English synn, with cognates in other Germanic languages. Etymologically it seems to carry the concept of guilt, of having trespassed, or committed wrongdoing. It may have come directly into the Germanic languages from the Latin sons, "to be guilty". It's used to translated the Hebrew chata ("to miss", "to go wrong") which carries archery language of being off target, to miss the mark; a fundamental failure to do what one ought to do. The Greek harmatia likewise is translated as sin, again meaning "to err" or "to flaw", to mess up basically.
In the Christian concept usually known as "Original Sin" the basic idea is that each and every one of us enters into this world already bearing a sort of mark or stain of sin upon us. In St. Augustine's formulation--the one generally embraced by Western Christians--the idea is that when Adam and Eve committed the original sin itself--disobeying God and eating the forbidden fruit--something fundamentally changed about their humanity, their very nature, it left a stain on their very humanity, and as such is passed on to all their descendents (you, me, everyone else).
Augustine was trying to address something very important:
Everybody sins. It doesn't matter who we're talking about, every person who has ever lived has messed up, has erred, has done wrong.. We have all missed the mark of God's righteousness, and this seems to be something within us, something so deep inside us that we're born with it. You don't have to believe the exact details of Augustine's theory in order to understand what he was trying to get at theologically.
Thus the idea of "original sin" is that from the moment we came into existence within our mother's womb, sin was already a problem for us.
Theologians have used a particular term to describe this innate human problem, they call it
concupiscence. Concupiscence is inwardly-driven selfish desire, it means that our desires, the things we crave, fundamentally are selfish. That we want to satisfy ourselves, and that our thoughts and actions are fundamentally geared toward selfishness, that even in our best moments we are usually putting ourselves first. The Protestant Reformer Martin Luther defined sin in Latin as "homo incurvatus in se", literally, "man curved inward upon himself".
Another term often used is "depraved" or "depravity" especially in Reformed Protestant circles, or even Lutheran circles, in the idea of "Total Depravity". Total Depravity is a generally pretty misunderstood concept as it would seem to indicate that it says people are entirely rotten, disgusting little rats. That's not what it means. The word "depraved" comes from the Latin depravare--bent, crooked, distorted. Again it's this idea that we are bent or curved inward. The "total" here refers the fact that there's not a part of us that is somehow left untouched by this problem of sin.
It doesn't mean that we are entirely rotten, disgusting little vermin. That's not what it means at all; because in all of this the Christian faith maintains that the fundamental goodness of all creation. The act of being human is a fundamentally good thing. And that's kind of where we get to the point of what salvation is and what it means.
The idea of salvation in Christianity is that God is not going to abandon His creation to destruction in death or through sin. God is actively at work to rescue--to save--His creation. All of creation. God, first and foremost, loves us, all of us, He loves all of His creation. After all, in the beginning God says of all that He made, "it is exceedingly good".
So salvation is God rescuing, renewing, and restoring the world. This He has done, is doing, and will finish in Jesus Christ. In Jesus God has become man, He has united Himself with our humanity, which is why we call Jesus "the God-Man", that He is both God and human, at the same time. And thus in Jesus and through Jesus God has set about the task of saving the world.
We look to the death and resurrection of Jesus as the centerpiece of this activity, as the locus of this redemptive work. Because we believe that by Christ's death on the cross and by His resurrection from the dead Jesus has taken hold of sin, of death, and destroyed it. By rising from the dead Jesus has overcome death, personally, in His humanity. The reality of what God has done in and for Jesus is therefore, now, a gospel--good news--to each one of us, that what God has done for Jesus He will do for us. Therefore, for example, St. Paul will write in Romans ch. 6 that all who are baptized are united to Jesus in His death and resurrection, being united to Him in death and united to Him in His resurrection. Thus we share, by the gift of God through faith, in Christ's death and resurrection. Which is why we then say that there is forgiveness of sin, that there is eternal life, the promise of resurrection from the dead on the last day.
So Christ is Savior because He has saved, and is saving, the world. By His death and resurrection He has overcome death, sin, hell, and the devil and has united Himself with us, and we in Him share in the sort of life that He has. With the promise that what God has done for Jesus God will do for us. That when Jesus returns at the end of history the dead will be raised up to new, bodily, eternal life. Not some far away place "in the sky", but this world. Because God is redeeming all creation, there will be a "new heavens" and a "new earth", all things will be made new, there will be an
apokatastasis panton (Greek: "restoration of all things").
So in short, we're sinners because we have a sin problem we stumble, fall, fail, and don't do what we're supposed to do. We also have a death problem, that is, we die. Salvation is God saving us--and all creation--from this mess and delivering us from the current state of how things are to the way they ought to be. That is how Jesus is the Savior, because He is the One saving us, God's agency through which and by which and in which He is making all things right.
-CryptoLutheran
