"Is anyone among you sick? Let him call for the elders of the church, and let them pray over him, anointing him with oil in the name of the Lord" (James 5:14, NKJV).
A few days ago, I saw a brief news report about a father and mother who were arrested and charged with negligent homicide for allowing their child to die of a treatable disease. Apparently, according to the report, the couple did not believe in seeking medical care because of their understanding of the Bible. They called the elders of the church to pray for their child and to anoint her with oil in the name of the Lord, but they believed the Bible passage that they were following also prohibited them from seeking medical care.
Now the parents are grieving the loss of a daughter and facing prison time. Did they love their daughter? I'm sure they did, or they would not have called the elders of the church to pray for her healing. Was their faith sincere? I have no reason to question it. They acted upon it with the expectation that their daughter would be healed. Did they misunderstand the Bible? Yes.
I have a lot of sympathy for the couple. I have made similar mistakes in reading the Bible. I too have read a passage, missed the intent of it, and added a prohibition that was not there. As far as I know, my misunderstandings have not cost anyone his or her life. However, I have missed the intent of God in reading Scriptures at times. I have read prohibitions into a text that were not there.
Faith in Christ saves us, but it does not make us infallible. We can be saved and still make very costly mistakes. That's why it's so important to continue learning the will of God in the Scriptures. We need to have as accurate an understanding of the Bible as possible in order to live as God intended.