“If you keep committing the same grave sin over and over again you’re becoming more like the devil and headed for hell while detaching yourself from Christ.”
That is not what Luther is addressing. He is saying that the value of the sacrifice is much more than any sin we can commit. He is not encouraging habitual sin; notice the “even if” in the statement.
No sin can separate us from Him, even if we were to kill or commit adultery thousands of times each day. Do you think such an exalted Lamb paid merely a small price with a meager sacrifice for our sins?
Now, how many times did Jesus tell Peter we are to forgive the repetitive sins of our brother? Do you think God forgives any less?
Do you use this to approve of your own sins?
Everyone must be in heaven than if you think this. Do you believe hell even exists and who goes there if you can commit grave sin and go to heaven
If they repent.