From: Matthew 9:1-8
The Curing of a Paralytic
 And getting into a boat He (Jesus) crossed over and came to His own city.  And behold, they brought to Him a paralytic, lying on his bed; and when Jesus saw their faith He said to the paralytic, "Take heart, My son; your sins are forgiven."  And behold, some of the scribes said to themselves, "This man is blaspheming."  But Jesus, knowing their thoughts, said, "Why do you think evil in your hearts?  For which is easier to say, `Your sins are forgiven', or to say, `Rise and walk'?  But that you may know that the Son of Man has authority on earth to forgive sins"--He then said to the paralytic-- "Rise, take up your bed and go home."  And He rose and went home.  When the crowds saw it, they were afraid, and they glorified God, who had given such authority to men.
1. "His own city": Capernaum (cf. Matthew 4:13 and Mark 2:1).
2-6. The sick man and those who bring him to Jesus ask Him to cure the man's physical illness; they believe in His supernatural powers. As in other instances of miracles, our Lord concerns Himself more with the underlying cause of illness, that is, sin. With divine largesse He gives more than He is asked for, even though people do not appreciate this. St. Thomas Aquinas says that Jesus Christ acts like a good doctor: He cures the cause of the illness (cf. "Commentary on St. Matthew", 9, 1-6).
2. The parallel passage of St. Mark adds a detail which helps us understand this scene better and explains why the text refers to "their faith": in Mark 2:2-5 we are told that there was such a crowd around Jesus that the people carrying the bed could not get near Him. So they had the idea of going up onto the roof and making a hole and lowering the bed down in front of Jesus. This explains His "seeing their faith".
Our Lord was pleased by their boldness, a boldness which resulted from their lively faith which brooked no obstacles. This nice example of daring indicates how we should go about putting charity into practice--as also how Jesus feels towards people who show real concern for others: He cures the paralytic who was so ingeniously helped by his friends and relatives; even the sick man himself showed daring by not being afraid of the risk involved.
St. Thomas comments on this verse as follows: "This paralytic symbolizes the sinner lying in sin"; just as the paralytic cannot move, so the sinner cannot help himself. The people who bring the paralytic along represent those who, by giving him good advice, lead the sinner to God" ("Commentary on St. Matthew", 9, 2). In order to get close to Jesus the same kind of holy daring is needed, as the Saints show us. Anyone who does not act like this will never take important decisions in his life as a Christian.
3-7. Here "to say" obviously means "to say and mean it", "to say producing the result which your words imply". Our Lord is arguing as follows" which is easier--to cure the paralytic's body or to forgive the sins of his soul? Undoubtedly, to cure his body; for the soul is superior to the body and therefore diseases of the soul are the more difficult to cure. However, a physical cure can be seen, whereas a cure of the soul cannot. Jesus proves the hidden cure by performing a visible one.
The Jews thought that any illness was due to personal sin (cf. John 9:1-3); so when they heard Jesus saying, "Your sins are forgiven", they reasoned in their minds as follows: only God can forgive sins (cf. Luke 5:21); this man says that He has power to forgive sins; therefore, He is claiming a power which belongs to God alone--which is blasphemy. Our Lord, however, forestalls them, using their own arguments: by curing the paralytic by saying the word, He shows them that since He has the power to cure the effects of sin (which is what they believe disease to be), then He also has power to cure the cause of illness (sin); therefore, He has divine power.
Jesus Christ passed on to the Apostles and their successors in the priestly ministry the power to forgive sins: "Receive the Holy Spirit. If you forgive sins of any, they are forgiven; if you retain the sins of any, they are retained" (John 20:22-23). "Truly, I say to you, whatever you bind on earth shall be bound in Heaven, and whatever you loose on earth shall be loosed in Heaven" (Matthew 18:18). Priests exercise this power in the Sacrament of Penance: in doing so they act not in their own name but in Christ's--"in persona Christi", as instruments of the Lord.
Hence the respect, the veneration and gratitude with which we should approach Confession: in the priest we should see Christ Himself, God Himself, and we should receive the words of absolution firmly believing that it is Christ who is uttering them through the priest. This is why the minister does not say: "Christ absolves you...", but rather "I absolve you from your sins..." He speaks in the first person. So fully is he identified with Jesus Christ Himself (cf. "St. Pius V Catechism", II, 5, 10).
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.