We have proof of resurrection in our daily lives right now! When we plant a seed it looks nothing like it will become when it grows, also it is dead but when it is put in the ground it grows (comes back to life) which is unexpected and becomes something totally different from a dead seed. So a seed to a plant is just like our dead bodies which go into the Earth and will become our resurrected bodies which is something that is not expected. I have learned this from the Bible. So during our lives on Earth we a step in our resurrected lives just as seeds are developed.