Tirukkural 359: Truth-Consciousness

He who so lives as to know Him who is the support of all things and abandon all desire, will be freed from the evils which would otherwise cleave to him and destroy (his efforts after absorption).

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.