I received another great question. This one, like the question regarding the Trinity, is probably best answered by blog than by sermon.
Why does Matthew 6:15 say that God will not forgive us if we don’t forgive others?
This is a very good question, there are other passages where Jesus predicates God’s forgiveness of us on our forgiveness of others.
"Judge not, and you will not be judged; condemn not, and you will not be condemned; forgive, and you will be forgiven; (Luke 6:37 ESV)
However, the bible also gives us other testimonies of scripture like Col 3:12-13 where Paul predicates our forgiveness of others on the God’s forgiveness of us.
Put on then, as God's chosen ones, holy and beloved, compassionate hearts, kindness, humility, meekness, and patience, 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. (Colossians 3:12-13 ESV)
Left with these scriptures we can easily get into a chicken/egg dilemma on which came first, God’s forgiveness of us or our forgiveness of others.
In answering the question I am going to appeal to what is called (in fancy pants theological circles) as the Rule of Faith. The Rule of Faith states that when we have some question on what a scripture means or what a scripture implies, we look to other passages in scripture for the explanation. That keeps the bible as the supreme source of our wisdom and also keeps us from subjecting the bible to fallible understandings of tradition.
I think the following scripture relieves the tension.
In him also you were circumcised with a circumcision made without hands, by putting off the body of the flesh, by the circumcision of Christ, having been buried with him in baptism, in which you were also raised with him through faith in the powerful working of God, who raised him from the dead. And you, who were dead in your trespasses and the uncircumcision of your flesh, God made alive together with him, having forgiven us all our trespasses, by canceling the record of debt that stood against us with its legal demands. This he set aside, nailing it to the cross. (Colossians 2:11-14 ESV)
This passage tells us that God forgave us our trespasses when he canceled the record of debt that stood against us, nailing it to the cross. The cross is the provision for our forgiveness with God. So, in one sense, we have all been forgiven of our sins long before we ever committed those sins, indeed long before we were ever born, insofar as we are Christians. In another sense, that forgiveness did not get applied to our heart until we sought God’s forgiveness through faith and entered into a relationship with God through faith in Jesus Christ. In even another sense, forgiveness is something we regularly apply to our lives as we live imperfect lives and regularly seek the transforming power of God’s grace through our confession of our sins as 1 John 1:9 reminds us.
If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. (1 John 1:9 ESV)
If we are the kind of people who humbly recognize the graciousness of God in forgiving us before we were ever born, and who humbly recognize that God forgave us when we came to Christ and who humbly seek forgiveness as God brings to mind the parts of our lives that still need the cleansing of unrighteousness; then we are going to be the kind of people that are ready to forgive others when they come to us in humility, seeking our forgiveness. If we aren’t, then this reveals to us that we have a very serious spiritual problem that needs to be dealt with. It doesn’t neccesarily mean that we aren’t saved (though a person who is persistently and characteristically unforgiving should seriously look at the authenticity of their faith), nor does it negate the truth of Col 1:13-14 which says that we have the justifying work of forgiveness when we come to Christ.
He has delivered us from the domain of darkness and transferred us to the kingdom of his beloved Son, in whom we have redemption, the forgiveness of sins. (Colossians 1:13-14 ESV)
As the study note in the ESV Study Bible on Matthew 6:15 suggests:
“Jesus reemphasizes the importance of forgiving others, indicating that there is a direct relationship between having been forgiven by God and the forgiveness that his disciples of necessity must extend to others. As in v. 12, forgive your trespasses here refers to the restoration of personal relationship with God, not to initial justification." (ESV Study Bible Notation)
It does mean that until we demonstrate that God’s Spirit has worked in our hearts so that we become forgiving people, we will not fully experience the transforming power of God’s forgiveness for us.
Keep the good questions coming.
Grace and Peace,