Do you mortify; do you make it your daily work; be always at it whilst you live; cease not a day from this work; be killing sin or it will be killing you.Of the Mortification of Sin in Believers Chapter 2
That is why the unregenerate person cannot understand the urgency of the gospel message: until they see the depth of their sin and the holiness of God, they find no reason to seek remedy for their condition.
When I turn to the map of the world I must say the same thing. It matters not what quarter I examine: I find men's hearts are everywhere the same, and everywhere wicked. Sin is the family disease of all the children of Adam.Old Paths, Ch 7
You can never part with sin soon enough; it is a cursed inmate, that will surely bring mischief upon the soul that harbours it. It will set its own dwelling on fire.Works 7:147
At the heart of all sin is a lie. The lie says to all of us in our sin, "The act you are now doing, the desire or attitude you are now feeling is not very bad because there are much worse things, not very bad because everyone else experiences the same things, not very bad because you can't help it, not very bad because there is no God, or, if that won't work, God knows you are but frail and weak and he will tolerate and pity your sin." There are a thousand distortions of the truth which sin brings with it into the human heart, so that Jeremiah cries out, "The heart is deceitful above all things and desperately corrupt; who can understand it?" (17:9).
God is love. But the supreme object of that love is himself. And because he loves himself supremely he cannot suffer what belongs to the integrity of his character and glory to be compromised or curtailed. That is the reason for the propitiation.Redemption Accomplished and Applied, 28
Sin may be comprehensively defined as lack of conformity to the law of God in act, habit, attitude, outlook, disposition, motivation, and mode of existence.Concise Theology, Section 31
Sacrifice views the atonement from the perspective of guilt, propitiation from that of wrath, reconciliation from that of alienation. Redemption has in view the bondage to which sin has consigned us, and it views the work of Christ not simply as deliverance from bondage but in terms of ransom.
propitiation does not detract from the love and mercy of God; it rather enhances the marvel of his love. For it shows the cost that redemptive love entails.Redemption Accomplished and Applied, 28
propitiation is not a turning of the wrath of God into love. The propitiation of the divine wrath, effected in the expiatory work of Christ, is the provision of God's eternal and unchangeable love, so that through the propitiation of his own wrath that love may realize its purpose in a way that is consonant with and to the glory of the dictates of his holiness.Redemption Accomplished & Applied, 27
As we read the Old Testament we do not find any warrant for discrimination between the fourth and the other nine. Nor indeed do we find any intimation in the Old Testament that in the Messianic age the Sabbath law would cease. If any commandment is emphasized it is the fourth.The Fourth Commandment according to the Westminster Standards
If we say that the fourth commandment is abrogated and the other nine are not, we must understand what we are saying. It would indeed be an amazing phenomenon that in the heart of the decalogue there should be one commandment -and one given such prominence and meticulous elaboration -that is totally different from the others in this regard that they are permanent and it is not. Surely no one will dispute that in the Old Testament the ten commandments constitute a well-rounded and compact unit. And surely no one will dispute that the Old Testament is itself throughout conscious of that fact.The Fourth Commandment according to the Westminster Standards
How monstrous a thing is rebellion! How direful a doom is prepared for the ungodly! My soul, never laugh at sin's fooleries, lest thou come to smile at sin itself. It is thine enemy, and thy Lord's enemy. View it with detestation
The fallen condition of all humankind in Adam is not the result of mere social conditioning but is such "by nature" (φύσει, physei)Ephesians, Evangelical Exegetical Commentary (Bellingham, WA: Lexham Press, 2015), 152.