The sages are an important part of the Hindu religion. They are called ‘Rishis’. These sages had understanding of things and places which normal people like you and I could never even imagine. Even in sages there were different types of sages based on their knowledge.
The DEVA-RISHIS were such sages who had complete understanding of everything in this world and the heaven. They could travel in all the 3 worlds and were close advisers of the Bhagwan. Narada is one such Deva-Rishi.
The Brahma-Rishis were as capable as the Brahma-rishis but the difference was that they stayed on earth, with the other humans. Their aim was to serve the humanity. Thus they preferred to live among the normal people.
The Raja-rishis were those sages who used to also live a normal life, like governing a kingdom and looking after their subjects. But at the same time they were highly learned in all the scriptures. King Janaka is such a Raja-Rishi.
The Maha-rishis had the complete knowledge but they did not involve themselves in the activities of the state. They wrote scriptures and hymns so that they could show the normal people the way to achieve Bhagwan’s blessings.
The Parama Rishis. The Kanda rishis and the Sutra rishis were the sages who had the understanding but were practicing to reach the ultimate positions.