In time of difficulty one of the most important things if not the most important thing is what you speak out of your mouth. In this instance we'll see what the Bible says about times of sickness. In Proverbs 4:20-22 it says "My son, attend to my words; incline thy ear unto my sayings. Let them not depart from thine eyes; keep them in the midst of thine heart. For they are life unto those that find them, and health to all their flesh." The word health is translated in the Strongs Concordance as- a medicine, a cure, a remedy, healing(health). If you keep God's word in your eyes, in your ears, and in your mouth it will produce healing or health in your body. Proverbs 12:18 says "but the tongue of the wise is health", the tongue of the wise is the tongue that speaks God's word. Proverbs 16:24 says "Pleasant words are as an honeycomb, sweet to the soul and health to the bones." Notice in all of those scriptures words produce healing in your body.
Proverbs 15:4 says "A wholesome tongue is a tree of life". That word wholesome is translated as the word health in the previous verses. Notice a wholesome tongue, a tongue that brings healing to your body. Death and life are in the power of the tongue and you will eat the fruit thereof (Proverbs 18:21). Sickness comes under death and healing and health comes under life. Death is anything that takes away from a quality of life and life is anything that adds to a quality of life and they are both in the power of the tongue. Understand the word of God is quick and powerful (Hebrews 4:12). And God and his word are one so what God can do his word can do (John 1:1). God's word always has the power to heal (Psalms 107:20). And if you believe, according to your faith be it unto you (Matthew 9:29).