Ṛṣibhiḥ, not ordinary persons, rsi, great... Just like Vyāsadeva. Mahārṣi, devarṣi, rājarṣi, ṛṣi. Formerly the brāhmaṇas, they were ṛṣis, and the kṣatriyas also, they were also just like ṛṣis. Therefore they are called rājarṣi. The spiritual science is not understandable by ordinary men. Just like Kṛṣṇa says in the fourth chapter, imaṁ rājarṣayo viduḥ: "This science was understood by the great rajarsis." Just like Mahārāja Yudhisthira, rājarṣi, Lord Rāmacandra, rājarṣi, Mahārāja Parīkṣit, rājarṣi, Mahārāja Ikṣvāku, rājarṣi. There are many. They were rājarṣis. The monarchy was not a cheap thing. The king was as good as a ṛṣi. Therefore they are called rājarṣi. The king used to rule over the citizens on the permission of the great, great sages. Just like Nārada, the Devarsi. He used to visit Mahārāja Yudhisthira. Similarly, other kings.
So spiritual science is meant for great personalities, brāhmaṇas, kṣatriyas, not for the vaiśyas and the śūdras. One has to get to the quality of brāhmaṇa and kṣatriya. So Kṛṣṇa says therefore, imaṁ rājarṣayo viduḥ. Unless one is ṛṣi, great ṛṣi, great saintly persons, one cannot understand the spiritual science. Therefore Kṛṣṇa says... Although Kṛṣṇa, the Supreme Personality of Godhead Himself... He can personally say anything which is authorized. Still He is giving reference to the statement of the ṛṣis. This is the way of Vedic understanding. You cannot establish anything dogmatically, "In my opinion it is like that." What you are, nonsense? What is your opinion? Even Kṛṣṇa says, ṛṣibhir bahudhā gītam. There are different kinds of ṛṣis—Gautama Ṛṣi, Kaṇada Ṛṣi... They have spoken different... In India there are six kinds of philosophies, but they are not recognized. Ṛṣibhiḥ, just like Devala Ṛṣi, Nārada Ṛṣi, Vyāsadeva, Asita Ṛṣi, Valmīki Ṛṣi, they are recognized. Ṛṣibhir bahudhā gītam. So they have got different philosophical ways to understand.
Therefore Bhāgavata summarizes that tarko 'pratiṣṭhaḥ śrutayo vibhinnā nāsau ṛṣir yasya mataṁ na bhinnam. He's not a ṛṣi who's opinion is not different. Yes. You are a ṛṣi. You have got some different system of philosophy. And if I want to become a ṛṣi, then I must disagree with you. Just like in the modern days it is going on, scientific research, philosophical research. Therefore it is said, nāsau ṛṣir yasya mataṁ na vibhinnam: "One cannot become a rsi unless he gives his personal different opinion."
Therefore Kṛṣṇa says, ṛṣibhir bahudhā gītam. Then which one we have to accept? We have to accept... That is stated in the Vedic literature. Nāsau ṛṣir yasya mataṁ na bhinnam. Śrutayo vibhinnāḥ. Vedic literature—Sāma, Yajur, Ṛg, Artharva—they are different. They are one, but we understand differently, according to our quality of understanding. Otherwise, all Vedic literature aims to understand Kṛṣṇa. Vedaiś ca sarvair aham eva vedyaḥ (BG 15.15). That is the purpose of Veda, to understand Kṛṣṇa. After many, many births of studying of Vedic literature, in the process of jñāna-mārga, when one becomes actually wise, bahūnāṁ janmanām ante (BG 7.19), when he is actually wise, jñānavān māṁ prapadyante, he understands Kṛṣṇa and surrenders unto Him. That is actually understanding. So chandobhir vividhaiḥ pṛthak.