Is it sin to take out medical insurance or legal insurance? Are we rather expected to put our faith in the Lord to take care of those things?
We were taught to pray, "Give us this day our daily bread" (Matthew 6:11), but God still commands us to work. "For even when we were with you, we commanded you this: If anyone will not work, neither shall he eat" (II Thessalonians 3:10). Working does not mean we don't trust God to take care of us. What it means is that God expects men to do what they can, and He will do what man cannot. Thus, Christians should not worry. "Therefore do not worry, saying, 'What shall we eat?' or 'What shall we drink?' or 'What shall we wear?' For after all these things the Gentiles seek. For your heavenly Father knows that you need all these things. But seek first the kingdom of God and His righteousness, and all these things shall be added to you" (Matthew 6:31-33).
Insurance is a financial arrangement. We know that life is full of unexpected problems. "Do not boast about tomorrow, for you do not know what a day may bring forth" (Proverbs 27:1). The proper way to handle them is to plan in advance for the possible difficulties. This is the lesson of the ant. "The ants are a people not strong, yet they prepare their food in the summer" (Proverbs 30:25).
"A prudent man foresees evil and hides himself; the simple pass on and are punished" (Proverbs 27:12). To be prudent is to plan ahead, so what if a disaster strikes before we can finish our preparations? Insurance is paying a small amount in advance to cover disasters. The insurance company voluntarily takes on the risk of a disaster on your behalf in exchange for prepayment. Because the insurance covers the large expenses, it means you don't have to personally hold in store as much money. You still have to save because insurance doesn't cover everything, but you don't have to save as much.
Having insurance doesn't mean you don't trust God. It merely means you are doing what you can to deal with life's uncertainties with what you have available to you. Many Americans have home, life, auto, and medical insurance. These don't prevent disasters, they merely help you cover expenses that come from unexpected disasters. What I trust God to do is watch over me and handle the things that I cannot handle on my own.