They are the things we cannot understand at all but which allow us to understand it all.
The difference between a miracle and nature is frequency. If the sun would rise once in a lifetime, it would be miraculous; if the sea would split every day, it would be natural. The deepest miracles are when nature becomes transcendent and when transcendence becomes natural. Ordinary people doing ordinary things often lead to ordinary results. Extraordinary people (you and I) doing extraordinary things (righteous acts) always lead to extraordinary results (a naturally miraculous, miraculously natural world).