Great question. A few things:
The rule that eating meat on any Friday was a
discipline of the church. It was put into place as a tool to help the faithful in sacrificing something and hopefully offering that sacrifice to the Lord in personal atonement for sin. In
Matthew 16:19, Christ gave Peter the power to bind a loose. This is a type of that Apostolic authority.
Let’s say your mother tells you, ‘FiberZilla, you are not allow to eat cookies on Sunday. It will help you learn temperance.’ As soon as mum isn’t looking, you hork down two or three cookies.
What was the real sin here? Eating cookies, or disobeying your mother?
A year later your mom says, ‘FiberZilla, you have done a great job with temperance. You are older now and I am concerned about sloth. To help teach you diligence, you are to mow Mrs. Johnson’s yard every Saturday.’
Is it ok for you to eat cookies on Sunday? Yes. Is it ok for you blow off Mrs. Johnson’s yard? No.
The next thing is that the absolute key to understanding Catholicism, is to know that it based on God’s love for us. We have hope that His mercy will look past our indiscretions and that He will forgive us and allow us to come home to Him. Everything that the Catholic church teaches is based on that idea. So if the church says that we are not to eat meat on Fridays, she does it because it is a tool to help us receive and rejoice in the love of God. It is to help us appreciate Christ’s total self-giving for our salvation. While there is absolutely nothing we can do on our own for our salvations, there is plenty we can do to open our hears to Christ. Sometimes denying yourself of something can do that. And since we are human, and we tend to be lazy, sometimes we need firmer direction to get us where we need to go.
Don’t think of it as, ‘If you eat meat on Friday, you go to hell.’ Instead, it is, ‘By not eating meat on Friday, you can, in some small way, participate with Christ’s suffering on the cross and bring yourself closer to Him.’
Finally, if you have died in a state of moral sin and are relegated to hell, there is no getting out again. We have hope that our Lord is merciful and will forgive us anyway and not send us there, even though that may be what we truly deserve.
Complex, complex question. I hope this has been helpful!