Thoughts have energy and vibrations. Positive thoughts encompassing the universe, and all things in it, living and non living, are highly energetic. The vibrations emanated from them have the power to activate chakras. Good karmas, give deep peace and contentment, and the benefits of good karmas are experienced sooner or later like a boomerang effect.
In the same way negative, constricted thoughts have negative vibrations. They have the capacity to imbalance chakras, and curtail progress and well being. They can give rise to disease, and death. God and Evil are within us. It is upto us the enliven either of them. Great saints by their thinking and positive karma have chakras vibrating to the optimum, such that they are in tune with God or the universal life energy and we can see that they have miraculous capabilities and powers. Our mind is the blue print upon which the course of our life can be mapped. We must be careful to design it well.