Matthew 1:21:

She will give birth to a son and you are to give him the name Jesus, because he will save his people from their sins.

In the popular mind the birth of Jesus has got nothing to do with evil. It's got to do with innocence - a baby in a manger in a stable among the cows and the donkeys, looked after lovingly by his mother and Joseph, visited by shepherds and wise men bringing gifts. It's an image reinforced by millions of Christmas cards and thousands of nativity plays.

But we seldom ask: Why was he laid in a manger? It was because selfish people would not make room for his mother in the inn.

And we don't recognise that Mary and the baby Jesus might not have had the support of Joseph - he was prepared to break off his engagement to Mary - he seemed to jump to the conclusion that Mary had been unfaithful.

And why was it shepherds and astronomers from the east that came to welcome the Son of God into the world, and not King Herod and the priests from Jerusalem? Because Jesus was born King of the Jews, the Son of David, and Herod was already the King of the Jews and he wasn't the Son of David, and he didn't want anyone coming along to challenge his power, so carefully built up with the help of Caesar Augustus. And the priests didn't want to annoy King Herod because their High Priest was appointed by him. Political self-interest ensured that Herod would try to destroy the child and in the process massacre the infant boys of Bethlehem.

This is the world the Son of God was born into - a world of sin and misery, where the strong dominate the weak, and the weak dominate the weakest. Where we serve our own self interests and often do wrong or fail to do what's right out of fear of what others may think. This is not some innocent lovey-dovey world where no one gets hurt. This is our world - the world of our newspapers and TV screens, our workplaces and homes. This is the world Jesus was born into.

From before he was born, from the moment he was conceived until his crucifixion, he suffered the tensions and dangers of this fallen world, this sinful world where he experienced all our vulnerability to evil. This world that would not rest until it destroyed him.

But where's the good news? Is this the message of the Bible - that God has come and meekly suffered as one of us? What good is that to us - that he's just one more statistic of crime, one more victim of inhumanity, one more person destroyed by sin? Joan Osbourne in her song One of us asked "What if God was one of us / Just a slob like one of us / Just a stranger on the bus / Trying to make His way Home".

Well, yes, that is part of the answer. He did become one of us. So much one of us that people passed him by and never noticed that he was the Son of God. We struggle to understand the incarnation, the humanisation of God. Theologians, in their struggles to understand over the centuries, have worked out what the Bible says and what it does not say about this. I'll try and put it in simple words you or I can understand:

God has always existed as three persons - Father, Son and Holy Spirit. To become the Saviour of the world, the Son, that's Jesus, took a human nature. He did not cease to be God. His coming down, his humiliation, consisted, not in ceasing to be God, but in becoming man - in taking a human nature from his mother Mary that was vulnerable to all the effects of sin and evil in this world, although he himself committed no sin, perpetrated no evil.

But what good does all this do? First, it tells us that God understands us. He knows our pain and suffering at the intimate level of personal experience. At the end there will not be one of us that can look in the face of God and say "You don't understand!" No matter how abused or hurt or tormented we are, we can look in the face of Jesus and say, "You know, Lord Jesus, you know."

In the Letter to the Hebrews we are assured that we have in Jesus "a great high priest who sympathises with us in our weakness, because he was tempted just as we are, although he did not sin". He not only suffered, he felt the temptation to hit back, to make his victimhood an excuse to do evil, to play the power games of the rich and influential and superior. And yet he never did. Even when Roman soldiers were driving nails through his hands and feet, he prayed "Father forgive them, they don't know what they're doing"! It wasn't just that he abstained from evil. He returned good for evil - he loved his enemies.

This surely is the beginning of the good news of great joy. The power of sin can be broken! Even the French existentialist Albert Camus recognised this in the life of Jesus. In his novel The Fall he says, "God's sole usefulness would be to guarantee innocence, and I am inclined to see religion as a huge laundering venture - as it was once, but briefly, for exactly three years, and it wasn't called religion. Since then soap has been lacking, our faces are dirty and we wipe one another's noses."

But that was then, this is now. What prevents us sharing Camus' pessimism concerning the indelibility of human guilt? Here we are, still the victims of evil, still giving in to temptation, still sinning, still feeling guilty. Like Shakespeare's Macbeth we still vainly try to erase our guilt "with some sweet oblivious antidote."

It is in this context that we really understand the good news of great joy - "You are to give him the name Jesus, because he will save his people from their sins." Jesus was born as the Saviour for the guilty.

The key to understanding this is that guilt and sin are not concerned primarily with our perception. We use the word "guilty" in two different ways. We talk about feeling guilty, when we have a bad conscience about something. We might even feel guilty when we ought not to - when we have been the victim of someone else's sin - we blame ourselves. The cure in that instance is to realise we are not guilty.

This helps us to see the other meaning of the word "guilty". That is when it is used in an objective moral or legal sense. If the verdict in a court of law is "Guilty", it is not referring to the state of mind of the accused. It is referring to his status before the law. He has committed the crime. He is guilty whether he feels it or not. He may have no conscience over what he has done, but he stands condemned. Similarly when God says we are sinners and guilty, he means we are guilty whether we feel it or not. We have broken his law. We have not acted in love. We have marred his world. We have caused untold hurt and misery. We have rebelled against him and broken relationship with him. As a result we are estranged and alienated from him. "The wages of sin is death" - not just physical death, but spiritual and eternal death.

That's why we need a Saviour. That's why Jesus came into the world - "to save his people from their sins." If you are drowning, you need to be saved from the water. If you are dying from an addiction, you need to be saved from that addiction. You need to be removed from what's killing you and it needs to be removed from you. But with sin it's more than a danger to you, it's more than an addiction - it is your sin and you have to take the consequences. You've done the crime and you must do the time.

This is the real marvel of the good news of great joy. Jesus says, "I have come to give my life as a ransom for many. I am the Good Shepherd. I lay down my life for the sheep." Or as the Apostle Paul says, "Christ died for our sins". This the secret of Christ's birth. He, more than any other, was "born to die". The Word became flesh, because only flesh can die. He came to take the place of condemned sinners - the place we deserve - the place of horror and darkness and estrangement from God. In the centre of that storm upon the cross he cried out, "My God, My God, why have you forsaken me?"

"The wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord." This is the amazing transaction of God's grace. The death I deserved to die, he died; and the gift he earned is given to me.

At the time of Jesus' death an amazing real-life parable was enacted. There were two men in custody - Jesus and Barabbas. One would be set free and one would die. Barabbas deserved to die and Jesus deserved to be set free. But in fact Jesus died and Barabbas was set free. Jesus died in the place of the guilty to set him free.

For me to benefit from what Jesus has done, I must accept it. All that is required is that I hold out my empty hands of faith to receive the gift, recognising I don't deserve it, but trusting in Christ alone for my salvation and hearing the words of Jesus, "Your sins are forgiven you. . . . Neither do I condemn you, go and sin no more." There is no condemnation for those who are in Christ Jesus.

If you feel the weight of guilt at this moment, perhaps of old sins, perhaps of current ones, come to Jesus and find forgiveness and peace with God. There is no sin too great, no stain too deep, no burden too heavy for Jesus to remove. The Apostle John said, "The blood of Jesus Christ cleanses from all sin".