In Mark 2:1-12 Why did Jesus say your sins are forgiven when the people brought him for healing? Is it because the man was paralysed due to his sins?

Jesus' response here is a bit surprising and it was the same for scribes of Jesus' days. Jesus' response to the paralytic is reminder to the people of that day and us.

1. The scribes and Pharisees believed in God and only one God. For them God coming as Man was not an understandable concept and the picture they had in their minds of a Messiah was that of a political leader. But Jesus was a mere Jewish rabbi who didn't have his own place to stay. Though He was God, the scribes never accepted it and believed it. Hence, Jesus by saying 'Your sins are forgiven' was making a claim that He was God - since forgiving the sins of a person was something only God could do. Jesus making a claim about His divinity by having the authority to forgive sins.

2. Another important thing Jesus tried to show was the state of sinfulness of mankind and their need for forgiveness. We don't know whether this man's sickness was a punishment of something wrong that he
did. We aren't told that. But, he was still a sinner just like everyone else in the world.(Romans 3:23) In a way, sin is the cause of everything that is wrong in the world today. The perfect world became imperfect because of sin. Through sin came death(physical and spiritual) to the world and all other diseases and ailments. So Jesus is again pointing to the greater need of the paralytic - forgiveness from his sins. And yes, Jesus doesn't stop there, but heals him completely.

So, we don't know what the particular cause of the man's paralysis was. But Jesus knew for certain He(and us too) was a sinner in need of forgiveness.