Samuel Rutherford (Communion Sermons, 75-76):
There is no sin we commit, if it were even to the treading of the blood of the New Covenant under foot, but we put a mask on it. The devil has taught men to baptize their sin with a new name, lest it should appear frightful. The murdering of the Son of God is done by an assembly of kirk-men, under a fair pretence: “We have a law, and by that law He ought to die." Idolatry is called humble kneeling. Satan is a coiner of false money, and upon his reprobate coin he puts the King of heaven's stamp. Herod's killing is sold for worshipping; killing of the saints is called good service to God. The devil comes to none and says, “I am the devil, hear my counsel, and I shall draw you to hell." No, he is not such a fool; he changes himself into an angel of light. Blessed are they who, in the wisdom of God's Spirit, can pull the mask off the devil and sin; see the devil to be the devil, and sin to be sin. If God's commandment be uppermost, it is no hard matter to discern sin. If God command a duty, no excuse in the world should cover thy disobedience.