why sin is a sin?
Basically sin is a sin because it detracts from being with God in the next life.
Are all sins equally bad?
no, all sins result in separation from God, and we need to repent to be in a right relationship with God. some sins are worse than others. This is why GOD handed out DIFFERENT punishments based on DIFFERENT sins.
What does true repentance mean?
Repenting is basically changing your mind about what you think, do or have done. In other words if pride or lust guide your thoughts and actions and you repent of that pride or that lust, your thoughts and action are now guided by the opposite of them, you should now think with love, humility, patience and compassion instead of thinking with that pride or lust. If you commit a sin and repent of that sin that means you will no longer do that sin and that goes for every time you commit a different sin and repent of it.
Repent; to change one's mind, to change one's mind for better, heartily to amend with abhorrence of one's past sins
source:yahoo!