While Jesus was having dinner at Matthew's house, many tax collectors and "sinners" came and ate with him and his disciples. When the Pharisees saw this, they asked his disciples, "Why does your teacher eat with tax collectors and 'sinners'?" On hearing this, Jesus said, "It is not the healthy who need a doctor, but the sick. But go and learn what this means: 'I desire mercy, not sacrifice.' For I have not come to call the righteous, but sinners." - Matthew 9:10-14
It's a very unpleasant thing to be told that we are sick, but it is positively devastating to be told we have a terminal illness. Denial is a common response. Some people can take weeks to come to terms with the diagnosis, and some simply never will.
That is how it is with sin. It is a disease which affects each and every one of us, yet so many people are in denial. They are certain that the diagnosis is wrong and that they are perfectly fine. They're happy, their life is on track and things are going just fine. They ignore the problem of sin completely and never spend a moment thinking about it. They can do this because it appears as though this disease has no symptoms, but nothing could be further from the truth. Take a look at the world around you. All of the crime, hate, violence and injustice we see on the news daily are the symptoms of someone's sin made real. It's undeniable.
"Alright, fine", they may say, "that murderer on the news is sick. But I'm not killing anyone!" No, certainly not. But we all sin, don't we? No one can honestly say that they have never hurt anyone, never lied, never cheated and never done wrong. We all know deep down what is right and what is wrong. Each of us at one time in our lives have made the choice to do wrong. All it takes is one time, and we are forever changed by that decision. We can never undo the wrong or change what we have done. We are forever infected with the disease of sin.
So you don't sin very much, you say? Yet, to argue about the seriousness of the sin is simply to argue about the severity of the symptoms. But if you're arguing about how insignificant your symptoms are, you've already admitted that you have the disease!
For each of us, no matter how mild or severe our symptoms, the disease always results in death. It would be foolish to argue that you're not going to die of a fatal illness because you don't "feel ill". A fatal disease is just that, and how it makes you feel or how you react to it is inconsequential.
But what is this "death" we're talking about? Don't we all die eventually anyway? When we speak of sin, we're not talking about the death of your body, but rather, the death of your spirit. God is a perfect, Holy being and He cannot tolerate our sin. For God, any sin is a rejection of his love and an act of rebellion. Once we have sinned, we cannot be with God in Heaven, for no one can stand in the presence of God with this illness in their soul. This is not just God punishing us for sin - it is the natural consequence of our decisions. When we choose to sin, we choose to be apart from our Holy God.
This is a difficult thing to accept! Can it really be that the price of a small, single sin is eternal separation from God? But we are born this way! God must have known we would sin before He created us, yet He went ahead and created us this way anyway. It's not our fault! It cannot be that God would make us unable to resist sin and then punish us for all eternity when we do the very thing we cannot avoid doing.
This is not the end of the story. God loves us and wants us to be with Him and so He gave His son Jesus to be our savior - and save us from our sin. He is the only way we can overcome our illness and be saved from the eternal death of our sin. But first, before we can ever accept what Jesus has done for us, we need to admit that we are sick. We must come out of denial, deny our pride and admit that we truly are a sinner. Only then can Jesus, the healer, come and take away our disease of sin so that we may live forever.
It's natural to ask, "Why did God permit us to sin at all?" It seems silly to permit us to get sick and then provide a cure for those who seek it. God loves us so much that it could not have been any other way. Please see the articles "Why Do I Need Jesus" and "Why Did Jesus Have to Die" for more details.