For anyone reading who does not remember their history lessons (shame on you says the history major) that Lutheran's have not been around forever. When the Catholic church was selling indulgences to get to heaven, Martin Luther said, that doesn't make any sense. So in 1517 when he was sitting around with his monk duties, he decided, if God grants us grace and expects us to have faith in Him, should we be buying our way into Heaven? The Bible clearly says you can't take your earthly things with you so how could you buy your way in?
Anyway, so why is Good Friday so important? When Jesus was nailed to that cross, He was both human and Son of God. Countless times he could have said, "thanks, but no thanks. These people mock me, beat me, laugh at me, treat me less than a peasant, berate and belittle me, mistreat my followers and believers, and the list could go on, so I am not going to save them. Why put myself through the pain and torture?" But He didn't. He endured the pain and suffering so we wouldn't have to. In one moment, his human weakness showed when He asked God to take it from Him, but then He realized, it was His Father's will and He would finish the task. We are FOREVER indebted to him. Today is vital for us. Now we wait, because we all know that for three days Jesus was dead, but soon, He will rise again. And someday, He will rise above earth and take all of us to heaven to be with Him and His Father for all eternity.