Something I just thought of is that before Jesus came, in the time of the "Old Testament", we can see how things were, without Jesus and the crucifixion and then His resurrection from the dead.
Even God's perfect law did not work.
Even God's own perfect judging of evil people did not work.
Even God's miracles did not get the results which God desired.
This was because, without Jesus God Himself can not do all that He really desires for us.
So, with Jesus God's own dreams come true; without Jesus coming here . . . even God could be having mainly nightmares.
He needs His Son Jesus, in order to have all that is pleasing to Him.
Also, by the way . . . Satan once was in Heaven, itself, but he got thrown out, because he tried to change Heaven. Even with all the good and love and perfect environment which is Heaven, Satan still became a mess of pride. So, changing circumstances and conditions is not enough.
Only with Jesus can we have all that is truly good
Every time we sin, we get a sample of how we could become
"worse and worse" (2 Timothy 3:13) if Jesus did not die for us and rise for us. When we sin, should be getting homesick to get back into God's love and peace and joy.