Jesus knew what the scribes were thinking. Mark did not make it clear how Jesus knew this. As a fully human being did Jesus read their facial expressions and the circumstances or as the fully divine Son of God did he understand it by virtue of his omniscience? How Jesus' humanity and deity interact is one of the great mysteries of scripture.
Jesus answered their question with a question - Mark 2:9
Jesus answered their question with a question of his own. Jesus often used this technique (11:29, 30). What is easier is a much more complex question than it appears to be on the surface. In one sense it is much easier to claim to forgive sins because there is no way to prove if they are really forgiven or not. At a deeper level it is much harder to forgive sins. Forgiveness required that Jesus go to the cross.
Son of Man - Mark 2:10
Jesus referred to himself as the Son ofMan more often than with any other title. The phrase was used in Daniel 7:13, 14 to refer to a heavenly being who became a messianic figure. Jesus claimed that he was the Son of Man and that he was able to forgive sins at that very moment, not just in heaven; but here on the earth. See the article on the titles of Christ. The healing was the proof that Jesus also had the authority to forgive sins.
Lake - Mark 2:13
The lake is a reference to the Sea of Galilee.
Tax collectors - Mark 2:14
In Mark 3:18 and Matt 9:9 Levi is called Matthew. The tax collectors were Jews who were appointed by the Roman authorities. They collected taxes for Rome and then often charged their own people outrageous fees for themselves. They were hated by the people and regarded as sinners. Because Levi set up his tax collector's tent by the lake he probably taxed the fishing industry in which at least four of the other disciples had earned their living.
Pharisees - Mark 2:16
The Pharisees promoted obedience not only to the written law of the Old Testament, but also to the oral law. The oral law were the traditions that were developed over the centuries as Israel tried to apply the scriptures to the ever changing life in Palestine. At its best it was an attempt to help people keep God's law. At its worst it was a man-made religion of works that tried to earn God's favor. The Pharisees were greatly respected by most of the Jews. The Pharisees refused to associate with those that they regarded as sinful people. They accused Jesus of blurring the lines between the righteous and the unrighteous.
Jesus came to call sinful people - Mark 2:17
Jesus made it clear that the reason he came was not to enjoy the company of the righteous people; but instead he came to call sinful people to respond to the preaching of the good news of God.
Fasting - Mark 2:18
Fasting was required only once a year in Judaism, on the Day of Atonement (Lev.16:29-31). In Jesus' day, however, many Jews fasted much more frequently. Fasting, especially when combined with prayer, was a powerful way of expressing repentance or neediness. Some in the crowd appealed to Jesus because his disciples did not seem to be practicing fasting. As their leader Jesus was expected to guide them into sacred practices. In Matt. 6:16-18 Jesus seems to have assumed that his followers would fast.
The bridegroom - Mark 2:19-20
Jesus responded by comparing himself to a bridegroom. Jesus expected his disciples to be rejoicing while he was with them. When he was gone there would be time for fasting.