How come God does not just heal every sick person?

The Bible promises us that one day sickness and suffering will be a thing of the past. For example, in Revelation 21:4 we hear the promise, He will wipe every tear from their eyes. There will be no more death’  or mourning or crying or pain, for the old order of things has passed away.”

However, we know that the brokenness in our world like sickness, is caused by sin, not an individual person’s sin, but by sin in the world - every person’s rejection of God and ignoring God. So until sin and evil are done away with forever, we will still experience brokenness in our world.  When Jesus heals people as recorded in the gospel accounts, he does so to give a taste of what it will be like when sin and evil are done away with forever.