@Charlie24
Another illustration just to show the difference:
You plant a orchard on the site of your future home. Your enemy corrupts the initial tree which corrupts the soil. All of the trees are bad trees producing bad fruit. These trees will die sooner or later.
You have an incorruptable seed which you plant in the orchard. It grows. It suffers under the poison of your enemy but always produces good fruit. Because of the poison it also dies, but it grows back incorruptible to the poison as a new kind of tree. The seeds it produces is life. If it affects the other trees it will make them like it is. Those trees will die but come back Incorruptible just like that new kind of tree.
You are going to judge those trees before you dwell in the orchard. The dead ones will be cut down and burned. Only the good ones will remain.
PSA version:
Same scenario. But to save the bad trees you consider the good tree to be the one bearing bad fruit. So you cut down the good tree to satisfy your requitement that only good trees remain when you move to the orchard.
Now you have all bad trees, but you look upon them as if they are good trees.
Some say you would then send another who could vaccinate the trees so that they would make good fruit by the time you move in.