Device 5: By presenting God to the soul as One made up all of mercy. In other words, Satan sometimes intimates that God is only a god of mercy and not holiness or wrath. Thus, since there is nothing whatsoever to fear from God, one may sin with impunity.
For remedies consider that.. .
1. It is the sorest of judgments to be left [by God] to sin upon any pretense whatsoever. The idea is that the worst judgment in this life is for God to leave us in our sin and the Holy Spirit not resist our sin in our consciences.
2. God is as just as he is merciful.
3. Sins against mercy [i.e., taking it for granted] will be the greatest and sorest judgments upon men.
4. Though God's general mercy is over all his works, yet hsi special mercy is confined to those that are divinely qualified--to those that love him and keep his commandments, who trust him, hope in him, and fear him.
5. The saints now glorified regarded God's mercy as a most powerful argument against, and not for, sin.