Iron and fire

Paramadvaiti Swami: Srila Prabhupada used to say, we have to keep the iron in the fire to keep it red hot, and then you can mold and form it into any shape you want. But if it becomes cold and black again, you can't do anything with it. Really, the most important thing to understand in our spiritual life is the dependence on and the attachment to the instructions and the spirit of service to our spiritual master.