You cannot confess of sin to be forgiven of sin if future sin is forgiven a person. 1 John 1:9 says if we confess our sins he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. The problem today is that Christians are not reading and believing this verse and many others.
Also, the Law that Paul talks about is the 613 laws of Moses as a whole or contract. Acts of the Apostles 13:39 says we are not justified by the Law of Moses. Paul never speaks against the keeping of the Law of Christ (Galatians 6:2), or the Law of the Spirit of Life in Christ Jesus (Romans 8:2), or the Perfect Law of Liberty (James 1:25), or the Command to Believe on Jesus and love one another (1 John 3:23). In other words, there is a huge difference between Old Testament Law (the 613 laws of Moses), vs. New Testament Law (Laws that come from Jesus and His followers).
In the book of Romans, Galatians, and Corinthians: Every time you see the word "law" or "works," just look at the surrounding context and you will see that it is in reference to the "Law of Moses" which ended with Christ's sacrifice. For the temple veil was torn from top to bottom at the cross, letting us know that the Law had ended. For if the laws on animal sacrifices and the priesthood ended with the temple veil being torn, then it is logical to assume that the whole of the Old Law is no more. In fact, that is what Hebrews 8:13 says. Jesus said at the Lord's supper (before His crucifixion) to His disciples that the Old was going to soon disappear (And it did with His death).
We are under a New Covenant with New Commands.
Paul was arguing for the necessity of the process of salvation called: "Justification" (which is a process of salvation that is without the deeds of the Law because it is based on God's mercy and forgiveness). This does not mean that there is not another step or stage in the salvation process after one is saved by God's grace. I believe this next step after Justification is Sanctification. One has to look at the whole counsel of God's Word to get a more fuller picture of salvation. But most are satisfied to just listen to their Pastor and for him to spoon feed them. They do not study God's Word on their own in prayer and just read and believe the plain text. They seek to change what the Bible plainly says. For example: Philippians 2:12 says work out your salvation with fear and trembling. This is obviously talking about fear because why all the trembling if it is not talking about fear? But men who want to justify sin on some level will say that "fear" does not mean "fear" and they will seek to change that word because they don't like it. So they say future sin is forgiven a person (Thereby leading people to treat God's grace as a license to sin on some level). For one does not have to practice sin in order to be condemned by that sin. One can think they can occasionally sin and not worry about confessing it to the Lord and think they are saved by thinking all their future sin is forgiven them (as long as they are not doing the really bad stuff like murdering all the time, or committing armed robbery, or being a inappropriate content star, etc.). Unfortunately, they do not need to worry about the other kinds of sins that Jesus said will destroy them. They do not heed the warnings of Jesus about how certain other sins can destroy their soul as Jesus warned us in Matthew 5:28-30, Matthew 6:15, Matthew 12:37, and Matthew 25:31-46. Why do they not care? Because their future sin is forgiven them. Thus, they have a license.