Are there certain sins with which you continually struggle? 
Are there certain sins with which you continually struggle? Are you bogged down by guilt from past sins that you just can't forget? Do you feel like Paul when he says "For what I want to do I do not do, but what I hate I do" Romans 7:15b? Does it feel like there is a constant war going on inside of you to suppress evil and do what is right? I know that I certainly struggle with sin daily and have many sins for which I pray to God for strength to overcome. When I was discussing forgiveness with my children, they even recognized how they are often disobedient to God, try to do good but then don't end up doing it. What a blessing it was studying this lesson to know that we have the forgiveness of sins!
This study helped me to truly reflect on the blessing of forgiveness that God gives us. Often times I treat forgiveness too casually and take it for granted. Whether it is responsively repenting of sins and being forgiven at the start of church, asking for forgiveness from God while praying, or asking for forgiveness from others, it is something that can unfortunately become old habit and become watered down. This lesson along with the Sunday morning Bible study on the Formula of Concord (you should go if you haven't had the chance yet!) really helped me get out of this type of thinking and really value the blessing we have in forgiveness of sins. 
When studying forgiveness, it is interesting to note the difference between objective justification and subjective justification. Objective justification tells us that Jesus paid the price in full for all sins ever committed. This is objective because it happened; it is a fact and we don't have to believe it for it to be true. Subjective justification means that we personally receive forgiveness of sins through our faith created by the Holy Spirit. The combination of objective and subjective justification gives me great comfort because I know that all of my sins are paid in full, and I know that is credited to me as righteousness through faith. I have comfort because Jesus did all of the work - I don't have to depend on myself to work even a small portion of my salvation. If I had to, I would constantly be questioning my salvation. What a blessing it is to have complete forgiveness of sins and salvation that was all accomplished not on our own accord by through Jesus perfect life, death, and resurrection.