313. THE SIXTH COMMANDMENT.
THOU SHALT NOT COMMIT ADULTERY.
In the natural sense, this commandment means not only not to commit adultery, but it refers also to willing and doing obscene things and thinking and speaking about lascivious things. That merely to lust is to commit adultery, is evident from the Lord's words:
Ye have heard that it was said by them of old time, Thou shalt not commit adultery. But I say to you, that everyone that looketh on another man's wife to lust after her, hath committed adultery with her already in his heart (Matt. 5:27, 28).
The reason of this is that when lust enters the will it becomes, as it were, deed; for allurement enters into the understanding only, but into the will, intention; and the intention of a lust is a deed. But more on this subject may be seen in the work on Marriage Love and Scortatory Love (Amsterdam, 1768), which treats, On the Opposition of Marriage to Scortatory Love (n. 423-443); On Fornication (n. 444-460); On Adulteries and the Different Kinds and Degrees of Adultery (n. 478-499); On the Lust of Defloration (n. 501-505); On the Lust for Variety (n. 506-510); On the Lust of Violation (n. 511, 512); On the Lust of Seducing Innocences (n. 513, 514); On the Imputation of Scortatory Love and of Marriage Love (n. 523-531). All of these things are meant by this commandment in the natural sense.