Gospel Guidebook: Getting and Keeping It Right 
Forgiveness of Unrepentant Willful Sins
Jesus Christ came into the world to save sinners. All people are sinners, but sinners who believe in the finished work of Christ as savior are inevitably sinners who need a savior, that is, sinners who recognize that they are sinners and want to be saved from their sins. When a sinner is brought to a recognition of his sins and is left to his own devices, he often becomes one of those who labor and are heavy laden. It is these types of people that Christ bids come to Him to find rest. What is the rest? It is a rest from their labors of seeking a righteousness of their own and their burden of knowing that they haven't achieved it. The truth is that we all have unrepentant willful sin in our lives. This is the reason why Jesus could say to the Pharisees that they strained out a gnat. They were so intent on ridding themselves of every little blemish, i.e., every known sin or potential for sin, and prided themselves because unlike the heavy ladened, they saw themselves as righteous. However, as they sought their own righteousness, little did they know that they swallowed a camel, thereby increasing their sin through hypocrisy and hatred toward others. This is the snare of self-righteousness, and I think this might be why Solomon wrote, "Be not righteous over much; neither make thyself over wise: why shouldest thou destroy thyself?" There is a righteousness that seems right to a man, but the end thereof is death. At the same time, the lack of such righteousness bears witness of sin, for whether a person swallows a gnat or a camel, sin abides with him. So, in the end, all of us have unrepentant willful sin. The issue becomes how we try to deal with it. Do we just ignore it or fool ourselves into thinking it doesn't exist? Do we become self righteous like the Pharisees? Or perhaps we take another route, like the Essenes or monks, and separate ourselves from society? Or do we come to Jesus with our unrepentant willful sin and all filthiness and just throw ourselves on His mercy? "But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness." So, if you are the type of person who is burdened by your efforts to strain out gnats, even if it appear to you to be a camel, you need to hear Jesus' voice saying to you, "Come to me and you will find rest." That means that we must come as we are with our gnats, camels, motes, and beams. Our only refuge is His mercy and He delights in showing mercy to people who are hopeless without it.
To conclude, I'd like to give my opinion on the Apostle Paul. He wrote openly about how he used to persecute Christians, but was shown mercy. It must have felt good to have repented of that sin. In fact, Paul was known to boast (in defense of his ministry) of his labors for Christ and how he exceeded all the other apostles. He even boasted in the persecutions, sufferings, beatings, and hardships he experienced. However, there was one thing that he kept concealed. It was his thorn in the flesh. What was it? He never tells us. Why not? Probably because he felt ashamed by it. As a former Pharisee who was keen on straining out gnats, he probably had some type of unrepentant willful sin in his life that drove him crazy because he wasn't able to strain it out. He was bothered incessantly by it, calling it a messenger from Satan. He even pleaded with the Lord three times that he might be delivered from it (probably in the same way that Moses pleaded with the LORD face-to-face that he might enter Canaan). However, God refused to deliver him from it. God wanted to keep him humble and reliant on Christ, rather than boastful in his own success at dealing with sin. So, he said, "My grace is sufficient for thee: for my strength is made perfect in weakness." Paul was forced to live with his sin, but through this experience he also learned firsthand that mercy and forgiveness don't extend only to repented sins, such as his persecution of Christians, but also extend to present and willful sins. And by this experience, he learned the importance of showing mercy on others, just as he was shown mercy. We must always remember that Christ died for sinners, not righteous or reformed people, and it is by believing this good news that we are saved.