"Fools mock at sin... " Proverbs 14:9
Fools are people who do not take sin seriously. They are not grieved by it nor are they concerned about the sin in their lives. Sin is a light matter to them.
The word "sin" could also mean sin-offering that it could be rendered "fools mock at sin-offering." Those who make light of sin are people, who, as a necessary result, also make light of the sacrifice for sin. Those who make a lightweight of sin makes a lightweight of the Savior.
But fools can only make a mockery of sin for so long. At the lake of fire, they will all realize that sin is fatally serious and what the Savior did on the cross, infinitely precious.
Repent my friend. Take sin seriously and the Savior earnestly. Come to Him in faith and be saved!