The good news at the end of the sermon was that we who are in Christ are free from our sin. Does this mean in eternity, or here and now? I know I'm forgiven of my past present and future sin but I feel like I can't stop doing certain sinful behaviors. What are your thoughts on this?
The Good News is that you are both free from sin's power now and will be for all eternity. A slave to sin, someone who doesn't believe, cannot not sin. But a believer in Jesus always has the option of obedience instead of sinning. This doesn't mean that the struggle against sin is easy (it's not!). And some types of sin are addictive in nature making the fight even more difficult, but if you believe in the gospel, you are free to not sin. Two thoughts on how to better fight against sin and then a reminder.
First, when tempted to sin ask the question, "What do I think this sin will give me that Jesus can't give me?" Meaning, there's something that you think this sin will give you that Jesus is unable to give you. Could be love. Or fulfillment. Or purpose. Or the feeling of being alive. But recognize the lie. Jesus does give you those things (and more!).
Second, know your Bible! Read it. Study it. Meditate on it. Memorize it. Without knowing your Bible, you will fall for the lies and false promises of sin. If you don't know the truths and promises of Scripture, you can't use them to fight sin. I have found that memorization of Scripture, in particular, to be the most helpful in my fight against sin. God's Word is a weapon -- a sword -- but you must know it to use it in your spiritual battle.
Now the reminder. Don't forget that Jesus forgives. "If we confess our sins, He is faithful and just to forgive us and to cleanse us from all unrighteousness." (1 John 1:9) Wrote that from memory, by the way. Even though we're free from sin's power; we're not sinless...yet (see 1 John 1:8). So, when we fight and fail, repent and know that Jesus forgives you.