So many people, even Christians, think that when something bad happens in their lives, that is given to them by God.
Verse 17 shows us, that God gives us only good things. Ne never gives us a bad thing. Even Jesus said that if the earthly fathers, know how to give good gifts to their children, how much more, God our Father will give good gifts to all those who ask him.
Some Christians say, that God either gave them the sickness, or wants them to be sick, to teach them a lesson. I personally think, that it is not true. Verse 18 says that we are the first fruits God created, and we are created in his image. Jesus healed people all the time. So obviously it is his will to heal us. And healing is one of those good gifts God has for us.