Real knowledge means to understand the last word of the Absolute Truth, the Supreme Personality of Godhead, and surrender unto Him, after knowledge. As it is confirmed in the Bhagavad-gītā, bahūnāṁ janmanām ante: (
BG 7.19) "After many, many births, one who is actually in knowledge, he surrenders." So Śrīmad-Bhāgavata practically confirms the same, that śreyaḥ-sṛtiṁ bhaktim udasya te vibho. Any person who does not take to the devotional service in Kṛṣṇa consciousness, simply indulge in dry speculation, kliśyanti, takes trouble...
Kliśyanti means "takes trouble"; ye, "persons." Kevala-bodha-lab..., simply to understand that "This is not matter, this is not spirit, this is not...," like that, and that there is no separate Supersoul, only one soul is there, and this conception of individual soul is misunderstanding, ignorance—in this way, there are volumes of books of, by Śaṅkarācārya especially, and later on, his disciples. They are very, very learned scholars, undoubtedly. By their scholastic jugglery they want to cover the Supreme Personality of God. They do not want to cover; they think that they are advanced. But Kṛṣṇa covers Himself so that they may not understand Kṛṣṇa. Kṛṣṇa does not want. Kṛṣṇa wants that one should surrender and take to devotional service. So Kṛṣṇa says in the Bhagavad-gītā that nāhaṁ prakāśaḥ sarvasya yoga-māyā-samāvṛtaḥ: (
BG 7.25) "I do not reveal Myself to everyone, one and all. No. I cover Myself." So these impersonalists, due to their, I mean to say, less intelligence, or misfortune, they cannot see Kṛṣṇa. So therefore, for them this remark is here that śreyaḥ-sṛtim, that "Actually what is auspicious, devotional service, if somebody gives that path away and takes to simply dry speculation, simply to understand..." Because jñāna means to understand what is the difference between matter and spirit. So they, of course, indulge in that process of knowledge. But simply by that speculation the result is that teṣām asau kleśala eva śiṣyate. The trouble which they accept for discriminating matter from spirit... There is trouble. You have to see so many Vedic literatures, and you have to understand the instruction of Upaniṣads and logic, and so many things there are to, I mean to say, back your understanding. So teṣām kleśala eva... Their, their profit is that the trouble which they accept for studying so many Vedic literatures to prove that the Absolute Truth is not person, that trouble is their profit and nothing more.