Protestants would have us believe that we are justified — saved from hell — by the exercise of faith in Christ plus nothing else. In fact, at least some will deny that the exercise of faith constitutes a human action, but that seems either completely irrational or like a grand exercise of special pleading.
But I digress.
I have been writing a series of posts in an effort to answer the question whether the Protestant version of sola fide is consistent with the Bible. I will of course allow the reader to decide for himself, but I think that it is increasingly clear that the basis for this doctrinal novelty is slim at best. On the other hand (as we have been seeing) there are masses of passages throughout the Bible which contradict the Protestant viewpoint. Here is another.
Then Peter went up to him and said, ‘Lord, how often must I forgive my brother if he wrongs me? As often as seven times?’ Jesus answered, ‘Not seven, I tell you, but seventy-seven times. ‘And so the kingdom of Heaven may be compared to a king who decided to settle his accounts with his servants. When the reckoning began, they brought him a man who owed ten thousand talents; he had no means of paying, so his master gave orders that he should be sold, together with his wife and children and all his possessions, to meet the debt. At this, the servant threw himself down at his master’s feet, with the words, “Be patient with me and I will pay the whole sum.” And the servant’s master felt so sorry for him that he let him go and cancelled the debt. Now as this servant went out, he happened to meet a fellow-servant who owed him one hundred denarii; and he seized him by the throat and began to throttle him, saying, “Pay what you owe me.” His fellow-servant fell at his feet and appealed to him, saying, “Be patient with me and I will pay you.” But the other would not agree; on the contrary, he had him thrown into prison till he should pay the debt. His fellow-servants were deeply distressed when they saw what had happened, and they went to their master and reported the whole affair to him. Then the master sent for the man and said to him, “You wicked servant, I cancelled all that debt of yours when you appealed to me. Were you not bound, then, to have pity on your fellow-servant just as I had pity on you?” And in his anger the master handed him over to the torturers till he should pay all his debt. And that is how my heavenly Father will deal with you unless you each forgive your brother from your heart.’ [Matthew 18:21-35, NJB; emphasis added)
You see, sola fide on the Protestant model is a dead-end road. If we do not forgive others, God will not forgive us. Forgiveness is Mandatory. Yes, I have written about this passage before. It is important! It is so important that the Lord Jesus included this subject in the prayer He taught His disciples: “Forgive us our trespasses as we forgive those who trespass against us.” And He goes on to exposit the prayer after teaching it, and He has just one thing to say about it:
Yes, if you forgive others their failings, your heavenly Father will forgive you yours; but if you do not forgive others, your Father will not forgive your failings either. (Matthew 6:14-15, NJB; emphasis added)
Not all the Protestant sola fide in the world will get us around this duty of love. If we have the love of God in us, then we will exercise it in forgiving those who have harmed us.
Aquinas, Etc. 
And what exactly gives us the capacity to forgive?
Hello Robert,
The grace of God gives us the capacity to forgive. But there are at least a couple qualifications to that. First, I observe that non-Christians are perfectly capable of exercising the virtue of forgiveness. Secondly and more importantly, giving us the capacity to forgive is not the same as compelling us to forgive. God does not overrule human freedom, which is ours by virtue of the fact that He created us as rational beings; rather, He perfects it.
The only example from the Bible that I can think of off the top of my head this early in the morning is a negative one, but I believe it still demonstrates my point. God told Moses that He would harden Pharaoh’s heart. But in almost every instance thereafter the Bible says that Pharaoh hardened his own heart, not that God did so. How do we reconcile these two facts? So far as I can tell, the only possible way is to affirm that God did so in such a way that Pharaoh also did so, freely and willingly. If Pharaoh had not been free to act, there would have been no justice in the judgment God poured out on him when he refused to let Israel go. He would have been a puppet on a string. But that is not what we are. That is not what he was.
In the same way, God gives us the grace to believe…and we are obliged (not compelled) to exercise it. And God gives us grace to forgive, but we must exercise it. If we do not do so, we will not be forgiven by God either. So the capacity to forgive comes from God, but its exercise is something that we must also do ourselves. I know of no other way to understand the Lord’s repeated admonitions to forgive. They make no sense if we lack the freedom to choose to do so, and there would be no justice in condemning us for a failure to forgive if we lack the freedom to choose. As St. Thomas Aquinas says, God perfects nature. He does not destroy it.
I hope this helps!
Peace,
Fred