Mankind should not ignore the cost of living in sin because God cannot disregard, take lightly, or dismiss man’s choice to sin.
Alexander the coppersmith did me much evil: the Lord reward him according to his works: (2 Timothy 4:14 KJV)
Evil does flourish in this world as it did in ancient biblical times too. Sin is present especially near those who strive to live in obedience to the standards God has set forth. Paul had once been a party to evil works and maybe was familiar with Alexander from his days of rebel rousing prior to his spiritual quickening alive along the Damascus Road.
Paul was inspired to write from first-hand experience according to what Alexander the coppersmith had done to him. The Bible does not allude or give much information as to what Alexander did only that it was evil in nature. Paul knew that God would exact a cost from Alexander for these evil works; while rewarding good works to those who remained steadfast amongst evil choosing to live according to the will of God.
Sin has been around since the day Eve ate of the fruit of the tree of knowledge with Adam following suit with his spiritually wayward wife. God covered them to atone for their sin and ushered them out of the perfect and sinless Garden of Eden and among the darkness and evil of the world.
Sin and darkness still operate in the world today. Sin always has a cost or a recompense for those who choose to follow after the evil and darkness of this world.
The Bible says:
Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap. (Galatians 6:7 KJV)
God cannot ignore or set aside the presence or cost of sin. When mankind chooses to dwell in sin the wages are eternal death; while those choosing to live by faith in obedience to God will reap eternal blessings.