From the very beginning, the devil has worked overtime to bring separation between God and His creation. This started in the Garden of Eden and immediately following the sinful choice of Adam and Eve to eat from the forbidden fruit, division entered their marriage. The first two humans, as a result of their sin, experienced separation from God and as a result—division between one another. That same pattern of division has infected all types of relationships, not just marriage. What happens when someone sins against us or offends us in some way, is it acceptable to hold a perpetual grudge? Will God accept me if I reject others?
Is God Holy?
In order to answer this question, it’s essential to ask ourselves a very important question and then answer it from the pages of Scripture. Is God holy? Is God like us? Is God distinct from us? As we examine the revelation of God from the pages of Scripture, we come to learn that He is distinct, separate from us, and higher than His creation. In short, God is holy. Regarding God’s holiness, we must learn two things:
- One upon a time, God’s holiness rejected us as sinners.
- Only in God’s holiness is it possible for us to be reconciled to God.
Has God Forgiven You for Your Sins?
When we read of God’s holiness, it’s a truly terrifying thing. Consider the scene that God paints for us in Isaiah 6 where the enthroned God is seen in the vision by the prophet Isaiah. Helpless and guilty sinners in the presence of an all consuming holy God is a terrifying thing, unless we are embraced in God’s love through His Son Jesus Christ. As we continue to read the Bible, we see that God not only possess a hot wrath for sinners, but He is also a merciful God who loves to forgive sinners. We see this in the love of the Father sending the Son who died for us in love (John 3:16). Consider the vast love of God who reconciles guilty sinners by sending His Son to die in their place (Rom. 5:6-11). Who does this? What kind of God is this according to the Bible? Simply put, our God is a God of mercy, love, forgiveness, and reconciliation. There is no other god like Him.
Is Holding a Grudge Sinful?
All through the Bible, we see the clear teaching of unity. God demands unity among His people and within His church. The teaching of unity is built upon a firm foundation of God’s grace, and therefore, God demands, expects, and commands us to strive for unity. Nothing else will be acceptable. God will not forgive you for holding a grudge in perpetuity. If you refuse to forgive others, God will not forgive you. What exactly was Jesus teaching in Matthew 6:14-15? Jesus said, “For if you forgive others their trespasses, your heavenly Father will also forgive you, but if you do not forgive others their trespasses, neither will your Father forgive your trespasses.”
The Mandate of Forgiveness and Unity in Christ
In his Systematic Theology, Wayne Grudem addresses the issue of unity by writing:
Paul can command the church to live in unity because there already is an actual spiritual unity in Christ which exists among genuine believers. He says, “There is one body and one Spirit, just as you were called to the one hope that belongs to your call, one Lord, one faith, one baptism, one God and Father of us all, who is above all and through all and in all” (Eph. 4:4–6). And though the body of Christ consists of many members, those members are all “one body” (1 Cor. 10:17; 12:12–26). 
The facts remain, God has mandated the horizontal forgiveness of others under the reality that we have experienced this glorious vertical forgiveness from Him. If we have received the forgiveness of sins through Jesus Christ, who are we to withhold forgiveness from others (Eph. 4:32)? In Colossians 3:12-17, Paul makes this point clear. He writes, “bearing with one another and, if one has a complaint against another, forgiving each other; as the Lord has forgiven you, so you also must forgive” (Col. 3:13).
As we follow Christ, we are to follow Him in acts of forgiveness. Our calling within the church is to bear with one another and to forgive each other as we strive for unity among the brethren. Charles Spurgeon once said the following:
Satan always hates Christian fellowship; it is his policy to keep Christians apart. Anything which can divide saints from one another he delights in. He attaches far more importance to godly intercourse than we do. Since union is strength, he does his best to promote separation. 
Will God forgive you for holding a grudge? No—He will not. However, if you’re a true Christian, you demonstrate the reality of your faith by how you forgive others and the priority you place on unity within the church. When you forgive others and repent of holding a grudge, you can expect your Heavenly Father to forgive you too. Therefore, do not let the sun go down on your anger, and give no opportunity to the devil (Eph. 4:26-27). That’s a message for the church as a whole—not just your marriage.
- Wayne A. Grudem, Systematic Theology: An Introduction to Biblical Doctrine (Leicester, England; Grand Rapids, MI: Inter-Varsity Press; Zondervan Pub. House, 2004), 876.
- Charles Spurgeon, Spiritual Warfare in a Believer’s Life, ed., Robert Hall, (Lynwood, Washington: Emerald Books, 1993), 115.