Tirukkural 203: Dread of Evil Deeds

To do no evil to enemies will be called the chief of all virtues.

Image of Satguru Sivaya Subramuniyaswami
Sadhana is performing the same discipline over and over and over again. Just as we methodically exercise the physical body to build up its muscles, we perform spiritual disciplines over and over again to strengthen our spiritual, inner bodies.