"of devastating service"

Change the world by changing yourself. Heal the world by healing yourself. Find a need and fulfill it. Service is the greatest form of spiritual practice.  

Everybody can be great because everybody can serve. You don’t have to have a college degree to serve, You don’t have to make your subject and verb agree to serve. You only need a heart full of grace. A soul generated by love.  - Martin Luther King Jr. 

The Sanskrit word for service is seva, that is selfless service. Service as a devotional practice is to perform an act with no intent for personal gain or acknowledgement. Service may include acts such as sweeping the temple, preparing for a puja (ceremony) or feeding people. The spiritual practice of seva is karma yoga, the yoga of action that brings together service with devotion to God.

Karma yoga, as explained in the Bhagavad Gita, the conversation between Krishna and Arjuna on the battlefield [of life] is selfless service unto humanity; the yoga of action which purifies the heart and prepares the attainment of Knowledge of the Self. The adjective “devastating” refers to the destruction of all attachment or egoism, when performing service to humanity. Such a path may be initially filled with desolation, and challenges but leads to purification of the heart.