In plain words
Even when King Daśaratha wished to crown his son Rāmacandra, he sought the permission of the sage Vaśiṣṭha. Whatever task had to be done, they were ready to take the counsel of the maharṣis. The reason is that those maharṣis had no selfishness or self-interest at all. The welfare of the world was all they looked to. ‘May all the worlds be happy’ was their whole aim. It was by having the shelter of such maharṣis that, under the rule of the kings, the land prospered in plenty. Those maharṣis held mantra powers, weapons of mantra, without measure. They were not to use those weapons in anything that was the form of the world. In these wars there are two kinds of war. One is to wage war for selfish ends. The other is to wage war for the good of others. Among the kinds of learning there are two kinds. The vows of Satya, kept for the welfare of the world, for the good of the world. The selfish vows, kept for the harm of the world. All the learning pursued for selfish ends, for self-interest, they called demonic learning. All the learning pursued and studied for the good of the world they called Brahma vidyā. Those who learned such Brahma vidyā were the ṛṣis of those days. They had great mantra power. Today, in selfish learning, machine power is great. Machine power has only a small limit. Of mantra power one cannot say it is this much or that much. Any amount of power can come to it. Yato vācā nivartante aprāpya manasā sahā: it has a power that the mind cannot tell nor speech describe.
Their rule was that the weapons held by the great ones who had kept the vow of Satya should be handed on only to those who had come down for the uplifting of the world. That is why Viśvāmitra came to King Daśaratha and took Rāma and Lakṣmaṇa away to guard the sacrifice. Holding that these weapons must be handed on only to great beings come down to establish Dharma, he gave Rāma all the weapons he had. Through them Rāma went on to destroy all the demons who stood in His way in the Daṇḍaka forest. The sage Agastya too did the same. There too he gave Rāma the whole of his imperishable protection. Through it the slaying of the demons went on. And who was it that taught them their learning? A man of great learning. The sage Viśvāmitra went on teaching them fine learning. Who taught Arjuna his learning? Droṇācārya, who had searched through all learning.