It is so obvious that this legalism is contrived and designed to confuse and return to bondage those that are totally saved. If you don’t do that you don’t get a lot of donations on Sunday. I think it is from the devil.
To believe you have to do “works” to be saved is to doubt that Christ died for your sins. Doubting God(not trusting), in itself, is a sin. God’s Grace is a gift to us, nothing we can do to earn it. We aren’t capable.