"but if you do not forgive others their trespasses, neither will your Father forgive your trespasses."
If we don’t forgive others, then we won’t be forgiven. This is fundamental to the gospel. We are saved by grace, but grace activates a life of graciousness. Titus 2:12 - "training us to renounce ungodliness and worldly passions, and to live self-controlled, upright, and godly lives in the present age," We can’t hold onto Christ and hate our neighbor. Christ's love cannot stay in an unforgiving heart. If we will have the fullness of Christ and walk with him, then we must walk as he walked and act as he commands us.
The promises of Scripture cannot be separated from the commands. We can’t say, “I have the privileges, but I won’t be obedient.” Both go together.
First, forgive because you’ve been forgiven. We have obtained mercy free of charge. We could be in hell forever, but God has spared us. Isaiah 38:17 — "Behold, it was for my welfare that I had great bitterness; but in love you have delivered my life from the pit of destruction, for you have cast all my sins behind your back." It was not because of our own goodness or righteousness; it was not because we’re better than others. It is entirely because of grace that Christ died for us, the Father chose us, and the Spirit gave us power. Let us acknowledge our own INDEBTEDNESS, and we’ll feel an obligation to others. Matthew 6:12 - "and forgive us our debts, as we also have forgiven our debtors." Let the love of Christ boom in your heart, and you’ll forgive people.
As Christ’s joy, power, and goodness is felt, it stirs up love towards our neighbor. When his love comes in, then hatred goes out. You cannot touch fire without being burned, and you cannot love Christ and hate people. You can’t have joy, and be unforgiving.
Secondly, when bitterness creeps in and evil thoughts towards another, then deal with it. Take your hurt feelings and mistreatment to God. Confess your sins. Say, “I do not have a right to be unforgiving. Let me forgive from the bottom of my heart. Teach me what it means.” Matthew 6:14 - "For if you forgive others their trespasses, your heavenly Father will also forgive you,"
Christ is well pleased for his righteousness sake. Vengeance is his. He will repay. He will give them shame and sorrow, and when he repays, then it is forever. Let this thought make you weep. Moan for them and mourn. They are going to pay far more than they ever imagined for rejecting Christ. We ought to pity them in the highest measure.
Likewise, he also gives repentance through conviction, so pray for them. Don’t offer mere religious speech, “Lord, bless them,” but know that he blesses through means. Cry out, "Fill their faces with shame, that they may seek your name, O LORD [Ps 83:16]." Pray for them to understand, and know that God does rightly always. They get away with nothing. They’ll repent, just like you, or they will perish.
Thirdly, forgiveness makes us happy! It removes the burden. We don’t have this obstacle between us and God. Matthew 6:15 - "but if you do not forgive others their trespasses, neither will your Father forgive your trespasses." Now, we can go to him in prayer, and we draw nearer to Christ through our hardship. He gives us difficult people to make us better. He hurts us by the hands of others, so that we may heal. Joseph got to the throne by the envy and hatred of his brothers. God exalts us into Christ-likeness, and makes us more loving by the injustices of men. He makes us stronger by what we suffer. 1 Peter 3:9 - "Do not repay evil for evil or reviling for reviling, but on the contrary, bless, for to this you were called, that you may obtain a blessing."
The forgiving person is MORE LOVING. He has grown. He is more humble, and he walks more closely with God. Let us be like this - forgiving so that we may honor Christ, and make ourselves happy. Let us forgive because we’re commanded.
Finally, if we take the commands seriously, then we do well. We grow in grace, and show ourselves authentic. We have no right to live our own lives: we’ve been bought with a price to be like Jesus. 1 Corinthians 6:20 - "for you were bought with a price. So glorify God in your body." Let us give ourselves entirely to Christ for our own benefit, and the good of others.