Jesus was a man who lived about 2000 years ago. Some say he was God's Son, while others say he was just a good man and teacher.
The Bible where Jesus is mentioned most, speaks alot about who he was and why he came.
Many believe that originally we had a close relationship with God but we chose to go our own way. We ignored God and said God does not exist. Our refusal to believe in God and to do things that upset God caused a division.
Jesus came to make things right. Often called a Saviour and God with us. Looking at his life we can see how to live according to how God would have liked us to live. Jesus challenged those he came across to turn away from a life without God, and to return to God by examining their lives, putting things right, and following Jesus.
The ultimate demonstration of God's love was to allow Jesus to be killed by those he challenged. Dying so those who believed in him can have the relationship with God restored. But Jesus didn't stay dead but he rose again from the dead to bring hope of a better life here and when we die.
Here is a simplified explanation of why Jesus died.
Jesus' resurrection gives us hope, with Jesus coming alive after death then we are promised life after our own death to spend with God forever.