In plain words
My very prasāda comes sweet. Will the prasāda received from God come bitter? Never!” Some people, out of ignorance, think in that way.
Madhvācārya was a great devotee who established the Dvaita doctrine. He lived in the Kannada country. A devotee of Kṛṣṇa. Once he called his disciples: “Tomorrow is Bhīṣma Ekādaśī. All of you observe the Ekādaśī vow,” he said. For three days the disciples went without food or drink, thinking of God without a break. That night Madhvācārya appeared to them in a dream: ‘Do not cling to mere observances and struggle on. This is not sādhana. Do not let go of the principle of the doctrines. This is what I experienced in my life,’ he said. People today: “Sir! Ekādaśī, Ekādaśī!” they say, and for three days go without food. On the fourth day they mix batter for forty dosas. Is this Ekādaśī? On the fourth day, not dosa: we must add Prema. When that Prema enters, there is no hunger at all. They taught this So'ham principle precisely so that one might forget hunger and thirst.
Great souls teach mantras precisely to establish peace in the world
Once, Viśvāmitra was taking Rāma and Lakṣmaṇa to guard the yajña he had undertaken. King Daśaratha's sons were tender, and had never known any hardship till then; so Daśaratha grieves over what they will suffer in the forest. When they reached the bank of the Sarayū, “Rāma! Lakṣmaṇa, come here,” Viśvāmitra called, and they went up to him with joyful hearts. Then that great sage taught them two mantras called ‘Bala’ and ‘Atibala’. “Knowing that Rāma was an Avatāra, why must he teach them a mantra?”: so many have kept arguing about this episode. Though Rāma and Lakṣmaṇa were divine beings, the body, after all, lives by food and rest. So one mantra so that hunger would not come, one mantra so that sleep would not come: he taught them two mantras. Without these two, food and sleep, one can do any amount of sādhana.