What Is The Christian’s Greatest Sin?

In a blog post entitled “My Biggest Sin,” McKay Caston writes:

You couldn’t help it, could you? This is gonna be juicy, right? Could be. Okay, let’s get to it. What is my biggest sin? Of course, most of us probably think of the Top 10 list in Exodus. “Thou Shall Not…” But we’ve all broken every one of those. No surprise there. So what is my biggest sin? Here goes: Not believing that I have been fully forgiven, totally accepted, and am dearly loved by the Father. Sorry to disappoint you, but when I DON’T believe this, I get religious and become a Pharisee of sorts, who were the biggest sinners in Jesus’ day (because of their prideful, “I can do it if you just show me the rule” hearts). To look upon the work of Jesus on the cross as my judicial substitute and to NOT believe that I am fully forgiven, totally accepted, and am dearly loved is to cheapen the gospel. To think that I can add anything of my own merit is to severely diminish God’s glorious grace. It is an insult to the blood of Jesus. “So Lord, I believe. Help my unbelief.”

Jonathan Edwards seemed to suggest the same.  In his 25th resolution for his life he wrote:

25.  Resolved, to examine carefully, and constantly, what that one thing in me is, which causes me in the least to doubt of the love of God; and to direct all my forces against it.

HT: The Wonder Of The Gospel

6 Responses

  1. I am not sure I agree that unbelief is not considered part of the first commandment, nevertheless, the Divines intimate a similar degree of heinousness in sinning against more light and grace. Consider the following Larger catechism questions:

    Q. 150. Are all transgressions of the law of God equally heinous in themselves, and in the sight of God?

    A. All transgressions of the law of God are not equally heinous; but some sins in themselves, and by reason of several aggravations, are more heinous in the sight of God than others.

    Q. 151. What are those aggravations that make some sins more heinous than others?

    A. Sins receive their aggravations,

    1. From the persons offending if they be of riper age, greater experience or grace, eminent for profession, gifts, place, office, guides to others, and whose example is likely to be followed by others.

    2. From the parties offended: if immediately against God, his attributes, and worship; against Christ, and his grace; the Holy Spirit, his witness, and workings against superiors, men of eminency, and such as we stand especially related and engaged unto; against any of the saints, particularly weak brethren, the souls of them, or any other, and the common good of all or many.

    3. From the nature and quality of the offense: if it be against the express letter of the law, break many commandments, contain in it many sins: if not only conceived in the heart, but breaks forth in words and actions, scandalize others, and admit of no reparation: if against means, mercies, judgments, light of nature, conviction of conscience, public or private admonition, censures of the church, civil punishments; and our prayers, purposes, promises, vows, covenants, and engagements to God or men: if done deliberately, wilfully, presumptuously, impudently, boastingly, maliciously, frequently,obstinately, with delight, continuance, or relapsing after repentance.

    4. From circumstances of time and place: if on the Lord’s day, or other times of divine worship; or immediately before or after these, or other helps to prevent or remedy such miscarriages; if in public, or in the presence of others, who are thereby likely to be provoked or defiled.

  2. Joseph Randall


    I agree with you. Luther certainly thought unbelief was part of the first commandment! And if Luther said it, well . . . you know it’s gold!


    I don’t agree with the way everything was put in that quotation, but I thought it was a good exhortation to fight the way Edwards fought.

  3. Joseph Randall

    Hey Nick,

    I was thinking this morning about how the author of the book of Hebrews argues how much worse it is to sin against Christ’s work than to sin against the Mosaic Covenant:

    Hebrews 10:26-31: For if we go on sinning deliberately after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a fearful expectation of judgment, and a fury of fire that will consume the adversaries. Anyone who has set aside the law of Moses dies without mercy on the evidence of two or three witnesses. How much worse punishment, do you think, will be deserved by the one who has spurned the Son of God, and has profaned the blood of the covenant by which he was sanctified, and has outraged the Spirit of grace? For we know him who said, “Vengeance is mine; I will repay.” And again, “The Lord will judge his people.” It is a fearful thing to fall into the hands of the living God.

    Christ is all!


  4. I also remember reading In Gerard Wisse’s book Christ’s Ministry in the Christian an interesting take on Peter’s denial of Christ. Wisse suggested that only a Christian can deny Christ. Judas may have betrayed Him, but He never knew His grace and therefore could not deny the One who had bought Him with a price. I thought that was interesting. Wisse argued that a Christian could commit sins that an unbeliever could not.

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