There are material and immaterial realms. Spiritual and physical. Change in the material realm is well understood in science and in practical sense. We know how to make a clean thing dirty, and then clean again. We know how to bake cakes, and break windows, and move an object from one place to another. How do we effect spiritual change? How does a spirit change? And, more to the point, how do we make real change?
We can’t create something from nothing. Our God was spirit and material from the beginning, and he created matter from nothing. Spirit created matter, as we understand from scripture. Even secularists know this, and a base post-modern critique of ourselves notes that we have to draw our voice, our thoughts, our creative ideas from somewhere. Everything came from something. Christians would say that God is the first cause, and there are still others who would say that there is no certainty that there was a “first cause.” God is the only one who can create. In fact, the Devil and his team can do miracles, the only limitation of which is creativity. He can’t create.
Praying for hours and days increases our connection with the divine, with the thoughts and strength of God, it increases our love, it increases our spiritual strength. He is a source of strength outside of our material selves, a source much greater than ourselves. In the spiritual realm as in the material realm, this is how change takes place. We cannot truly change any other way: prayer. Or, “prayer” broadly understood as spiritual depth, relational connection in the spiritual realm, a deep bond of one spirit with another spirit.
This is what Malcolm X and Ghandi and MLK Jr understood, we have to have a strong spiritual bond and a strong bond with the Creator, or as Christians would call upon the Holy Spirit, in order to draw spiritual power, strength, the ability to make changes in the material realm. This is how real change is made.
This is what happens when the believers are filled with the Holy Spirit, as in Acts 2. It compels us to be together as one, to eat and pray together, to share in fellowship, and to pool our belongings and sell them as needed to help each other, to help those who are poor. This is what happened when people were fully engaged with what is happening with the spiritual realm, this is the feeling that happens, and increases by this (see the Gospel and Acts). What happens when people are fully engaged with the spiritual realm or the heavenly realm, they do creative miracles, creative acts of justice, they are willing and ready to die for Jesus.