Answer: - It has been mentioned earlier that Supreme God (Param Akshar Brahm) Himself appears on earth in a body and correctly imparts the true spiritual knowledge. The knowledge imparted by the Supreme God is known as Sukshm Ved (Tatvagyan).
God has explained in Tatvagyan that: -
Guru bin kaahu na paya gyana, jyon thotha bhus chhade moodh kisana |
Guru bin bed padhae jo praani, samjhe na saar rahe agyaani ||
Those Rishis (sages) and Maharishis (great sages) who did not find a Satguru, their state was such that they used to read Vedas but they could not understand the essence of the Vedas.
For example, in Shrimad Devi Bhagavata Puran (Sachitra Mota Type, Published from Gita Press Gorakhpur) on page 414 (in Fourth Skand), it is written that the Brahmins (Maharishis) of Satyug used to be complete scholars of the Vedas, and they used to worship Shri Devi (Goddess Durga).
Please think: - Shrimad Bhagavad Gita is the summary of the four Vedas. You are familiar with Gita ji, and must have read it as well. Is it anywhere written in Gita ji that one should worship “Shri Devi” (Goddess Durga)?
Likewise, it is nowhere written in the four Vedas that one should worship Goddess Durga (Shri Devi). Then what have these Maharishis understood of the Vedas? What scholars were these Maharishis of Satyug? The same Maharishis have this arbitrary principle that ‘Om’ mantra is the greatest, that is, the best and worship of Brahm is the best amongst all.
Dear Readers! Those who used to worship Brahm as their deity were ignorant. It is evident in Bhagavad Gita that worship of Brahm leads to a bad state (awful salvation).
Evidence in Gita: In Shrimad Bhagavad Gita Chapter 7 Verses 12 to 15, it has been mentioned that the worshippers of the three gunas (Rajgun Brahma, Satgun Vishnu and Tamgun Shiv), those with demoniac nature, lowest among men, evil- doers, fools, do not even worship me. These are the words of Speaker of the knowledge of Gita.
Then in Bhagavad Gita Chapter 7 Verses 16 to 18, the Speaker (Brahm) of the knowledge of Gita has stated that four types of people worship me – Artharthi, Aart, Jigyasu and Gyani. Then he has said that amongst these four I like 'Gyani', and a 'Gyani' likes me. (Gyani means knowledgeable)
In Bhagavad Gita Chapter 7 Verse 18, the Speaker of the knowledge of Gita says that these Gyani (knowledgeable) souls are generous (good), but they all rely on my Anuttam Gati, that is, bad / inferior state (awful salvation). In this verse (Gita Chapter 7 Verse 18), the Speaker of the knowledge of Gita (Brahm) is himself confessing that the salvation obtained by his worship is Anuttam (inferior).
It has been stated in Gita Chapter 7 Verse 19 that: -
Bahunaam janmanaam ante gyaanvan mam prapadyate,
VasudevH sarvam iti saH mahatma sudurlabhH ||
Translation: - The Speaker of the knowledge of Gita, Brahm, is saying that rarely a knowledgeable person at the end of many births worships me; otherwise, they keep ruining their lives in worshipping other gods-goddesses, ghosts and pitras (manes).
The Speaker of the knowledge of Gita has even described the benefit, that is, the salvation obtained from his own worship as Anuttam (bad / inferior) in Gita Chapter 7 Verse 18. Therefore, in Gita Chapter 7 Verse 19, he is saying that: -
It is very difficult to find a Mahatma who tells this that “Vasudev” is everything. He is the Creator of all. He is the destroyer of sins, the Giver of complete salvation, and He alone is worthy of being worshipped. This Master (Vasudev only) of the Lineage is Param Akshar Brahm. Only worship Him and not anyone else.
The Speaker of the knowledge of Gita has also himself stated in Gita Chapter 18 Verse 62 that “O Arjun! You may go into the refuge of that God in every respect. Only by the grace of that Supreme God, you will attain supreme peace and the eternal supreme abode (Satyalok).” (Gita Chapter 18 Verse 62.)
Then in Bhagavad Gita Chapter 18 Verse 46, the Giver of the knowledge of Gita has said that “the Supreme God from whom all the living beings have originated, from whom this entire world has pervaded, by worshipping that Supreme God while doing one’s natural actions, a human being attains supreme siddhi (salvation).”
Then in Bhagavad Gita Chapter 15 Verse 4, it is said that after understanding the Tatvagyan, one should search for that supreme state of the Supreme God, having gone where, a worshipper never returns to the world. The Supreme God from whom the world- like tree has extended, that is, the Supreme God who has created everyone; one should only worship Him.
This proves that those sages & great sages did not understand the profound mystery of the Vedas. They remained ignorant.