Adultery is wrong, as wrong as greed, hatred and breaking promises (1 Corinthians 6:9-10).  But it has an even greater relationship-breaking effect.  The Bible teaches that sex is designed to be expressed in marriage (Genesis 1:27-28) as a means of expressing love and producing children.  Any other expression of sexual desire will displease God, hurt others and shame our own consciences (1 Corinthians 6:18).  That was all written in the Old Testament law.  However, in these verses, Jesus did not only support God’s ancient commandments, He made them even more practical.

Fear, lack of opportunity and an internal moral sense of wrongness will keep many people from the act of adultery; but that is no reason for moral smugness.  Jesus said that lust is just as bad.  Indeed, it is so bad that radical measures need to be taken to prevent the cascade from lust to disaster (1 Thessalonians 4:3-8).  The heart is naturally lustful, but if that desire is starved, it has little power.  However, if it is fed through what the eyes see, and what the hands touch - then lust can easily become a raging inferno which can overwhelm the strongest of mental resolutions.  So, Jesus sees the wrong passion as equal to the wrong action.  And, in a way, it is more important to deal with before a wrong action is taken which cannot be undone.

Is the treatment for this problem to cut off a hand or gouge out an eye?  No.  Jesus is not advocating self-mutilation (there is no benefit in self-harming in an attempt to purify the soul).  He is making a big point in a highly graphic way – even if we feel it is repulsive.  He is saying that temptation needs to be dealt with at its source.  If looking at a person you are not married to fans the flames of wrongful passion, then don’t look.  If touching excites wrong passion, then don’t touch.  If you are married, do not deprive each other (1 Corinthians 7:1-5).  If you are not married but are free to marry (and the other person is also a believer), then get married lest the passions destroy your integrity (1 Corinthians 7:8-9). 

This is strong talking from Jesus; but it is necessary in every age and especially our own.  Spiritual disciplines of prayer, Bible reading and fellowship must be matched by practical disciplines.  We need to decide what we will not watch and what we will not touch.  It is a matter of the heart to agree with Jesus that His principle is right.  It is a matter of the heart to love Him so much that we choose what to see and handle.  Decisions are made in the heart about what will build us (and others) up instead of dragging us down.  Parents need not be shy in talking with children and teenagers; youth leaders should not be afraid to be clear and practical.  Church pastors must not shy away from such teaching.  And we all need to encourage each other to do it.