And Jesus said, Are ye also yet without understanding?

Do not ye yet understand, that whatsoever entereth in at the mouth goeth into the belly, and is cast out into the draught?

But those things which proceed out of the mouth come forth from the heart; and they defile the man.

For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies:

These are the things which defile a man: but to eat with unwashen hands defileth not a man.  Matthew 15:15-20

It is biblical to view offensive language as a symptom of a person’s spiritual condition.   Too often, however, I believe our Christian evangelical focus becomes not the spiritual condition of the unbeliever, but his/her offense.

When the offense of the unbeliever becomes the focus, conformity to the believer’s standard of behavior becomes the goal.  What good is it for the unbeliever to change his speech while remaining unconverted?

The Great Commission is not about cleaning up unbelievers.  If you and I get unbelievers to stop engaging in fornication, drunkeness and blasphemy, they will still die and go to hell.

Biblical evangelism is not concerned with outward conformity. The goal of biblical evangelism is an inward transformation brought about by trusting Jesus Christ as one’s only hope of salvation.   

Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.  2 Corinthians 5:17 

Note:  When did you last love a profane person?