if you buy something on Sunday (a sin)
...they actually teach that? Wow. (I can think of no reasonable justification for that being a sin).
MaximumZero nailed it, pretty much. I'd have to find the specific passage, but it's pretty explicit that buying or selling on the Sabbath is defiling it, which is a sin. Probably no point in dredging it back up at this point since the subject has changed.
About
The church I still get dragged to believes that any sin you commit can and will send you to eternal burning torment.
I wonder what kind of church that is
It's a Pentecostal Holiness church, which is pretty close to the extreme end of Bible literalism and conservatism. Little surprise that they believe things that way as a result.
The fact that they do believe in eternal torment Hell for conventional (as opposed to beast worshipping) sinners pretty much directly leads to the insane things they believe, and by following their logic I almost can't fault them. They believe that any sin, including not being saved and just having "original sin" is enough to condemn you to eternal Hell. As a result, you should get saved as soon as you can and basically do as little as you can that isn't written as being okay in the Bible, else you risk going to Hell forever.
Drinking at all, for example, is forbidden. The Bible just says to abstain from drunkenness, but why would you ever dare to
risk getting drunk when it could land you in Hell forever? Literally no risk in a finite lifetime is worth an eternity of unimaginable punishment, so you shouldn't take risks.
That's also why the Pentecostal Holiness church is such a Bible literalist denomination. If it's written as being bad in the Bible, don't dare do otherwise or you'll burn in Hell forever. Buying or selling on the Sabbath is defiling it, which is a sin, which sends you to Hell. Women can't teach in the church, or they'll go to Hell. Gays are going to Hell. Saying "Oh my God!" is taking the Lord's name in vain, which is sending you to Hell. See how it works?
as that is directly ignoring Matthew 12:31 and the extent of God's mercy regarding sinners, especially considering everyone has faults of their own.
Pentecostal Holiness is a religion of fear, pure and simple, and they interpret that passage accordingly. They don't dress it up that way and do go around saying "God is good," all of the time, but as a kid fear is all I ever took away from it. If I messed up, I'd go to Hell forever. You could be forgiven of your sins by God,
but you had to ask, and He had to accept your apology. If you messed up, got in a car wreck or had a heart attack five minutes later without asking for forgiveness, off to Hell with you. Didn't matter if you had been an abiding Christian for 30 years prior. You just shouldn't have let yourself get into the mindset so that you'd do something bad. God was good, but God was absolute and unrelenting.
Clearly, not all of them believed that way. The more sane ones would just say "Well, he just lost some of his reward in heaven," instead of saying he went to Hell. Or, "I'm sure God gave him a chance to repent before he died." Most people when presented with insanity like that take away a personalized more sane version. But... there were the serious ones, and as a kid I was too scared to do anything but take it completely seriously. I spent a year or more of my life seriously stopping every few minutes to ask God to forgive me of something I didn't even know I'd done, because I didn't want to go to Hell.
I do want to clarify that the
people usually aren't bad and this isn't like the Westboro Baptist Church where they go around doing dreadful things to forward their agenda, but the beliefs are pretty awful at times. They usually are nice people and help the community. They give out food to the needy. They
try to be the best people they can. The beliefs just skew what is "good" in this case too much for me to accept.
So... sorry for dragging that back into the discussion and painting Christianity in almost the worst light it could be painted in, but I want to frame things for those who wonder why I seem so bitter at times.
This kind of teaching still happens to kids around here, in the 21st century.