What Does Jesus Mean When He Says "If Your Hand Causes You To Sin Cut It Off?"" Matthew 5:27-30

Adultery

27 “You have heard that it was said, ‘You shall not commit adultery.’

When Jesus begins with the familiar phrase, "You have heard it said.", he is referring to the Old Testament teaching of the Law by the Jewish leaders. This was the 6th commandment given to Moses and the Israelites. The issue at hand was the Pharisees only interpreted this as a single adulterous act by  married person, not the deeper aspects of the heart which Jesus will soon further expound upon. 

28 But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart. 

As was the case with Jesus' teaching on murder, Jesus is looking at matters of the heart.  Jesus says that when a person looks at another person lustfully to possess what they is not rightfully theirs, they commit the sin of adultery in their heart. "

Importantly Guzik states there still is a difference between the two,

However, it is important to understand that Jesus is not saying that the act of adultery and adultery in the heart are the same thing. More than a few people have been deceived on this point and say, “I’ve already committed adultery in my heart, so I may as well do it in practice.” The act of adultery is far worse than adultery in the heart. Jesus’ point is not to say they are the same things, but to say they are both sin, and both prohibited by the command against adultery.

Lust is a huge issue in our society with both men and women.  The pornography industry, which relies on lust, is a 12 billion dollar industry bigger than CBS, NBC and ABC combined.  Pornography distorts sex, which is given as a gift from God for pleasure in marriage, into destructive habit which ruins lives. It is another example of our Lutheran confession when we say, "I am in bondage to sin and cannot free myself."  But the Good News is we have been freed from sin by Jesus' work on the cross.

29 If your right eye causes you to stumble, gouge it out and throw it away. It is better for you to lose one part of your body than for your whole body to be thrown into hell.

Obviously Jesus doesn't literally mean plucking your eye out if you are prone to lust.  Even if one did remove their eye, it wouldn't prevent lust, which is also fed by fantasies of the mind. I think we might rightly say that Jesus is saying, "Do everything in your power however radical it is to remove the temptation that cause you to sin." For instance if your issue is lust you might block any pornographic site on your internet, or not shows that portray sexual immorality. 

Guzik says, "The trouble with a literal interpretation is that it does not go far enough! Even if you did cut off your hand or gouge out your eye, you could still sin with your other hand or eye. When all those are gone, you can especially sin with your mind."

When Jesus says if you don't gouge out your eye you will be thrown in hell, this is not to be confused with the gospel that we are saved by grace not works.  Lust doesn't cause to lose your salvation, but if lust becomes your master you will be in for hell on earth in one way or another.  

 30 And if your right hand causes you to stumble, cut it off and throw it away. It is better for you to lose one part of your body than for your whole body to go into hell.

Jesus repeats the same message using a different body part.  Again, Jesus is not teaching "mutilation",  but he is teaching that we must be willing to turn from sin and repent from behavior not in alignment with Him.  For an unbeliever if they don't repent from sin and turn to Jesus for forgiveness, it will send them to hell. For the Christian, if we allow our sinful nature to control our lives with something like lust or anger, we have surrendered one of the greatest gifts Jesus has given us in this life ... freedom!

Has lust become an issue in your life?  What are you willing to do to "cut it out"?  Why do you think Jesus is so radical in his teaching today?  Is he trying to take away "all our fun"?