What is sin? According to Christian believers, sin is the violation of God’s Commandments or a transgression against divine law. When one violates God’s commandments, he/she have sinned. The Bible has many definition of sin. But they all tell us that sin is about breaking God’s laws/commandments. Christians have 10 Commandments to follow. If a Christian would violate one of these then he commits a sin. Basically, sin is whatever that contradicts God’s command. This is how the Divine Command Theory, which is held by many Protestant Christians, defines sin. And this is also how other religions like Islam and Judaism defines sin.
On the other hand, for me, I do not define sin as that. Maybe I dont believe in sin at all. I believe that I have this thing called free will and no one is commanding me to do this or that or else I’ll suffer eternal damnation. So since I dont believe in sin and that I have free will, am I a bad? [Opkors not!] Do I know what is good and what is bad? [Opkors yes!]
I dont believe in sin but I believe in immoral acts. Immoral acts are acts that causes damage to others. That’s how I define bad [or sin to Christians]. Simple as that. Acts like killing or raping causes damage to others. Since it causes damage to others then I do not kill and rape. Now is gluttony or lust or envy bad/immoral? For me they are not unless they can cause damage to others. To others [I'm talking bout believers(most of them if not all)] they do not do bad things/immoral acts because that’s what the commandments say or that’s what their God say. What if their God would tell them to kill, would they? Look at 9/11 and the Crusades. These people are just afraid of the punishment of hell or they like the reward of heaven. They do not know what is really bad. Some of them are just forced [maybe] to not to do bad.
Unlike them, I really do know what bad/immoral is from the bottom of my heart. I do not do bad [immoral acts] just because I am forced to or I am afraid of hell or I want the reward of heaven but because I know from the bottom of my heart that it is bad [simply because it can cause damage to others.] :D
Lastly I dont like the idea of sin because it kind of takes away the essence of life which is absolute freedom. Man must have freedom in order to be human. Man must choose for himself what to do and what not to do and be responsible.