CC Ādi 1.51
সরহস্যং তদঙ্গঞ্চ গৃহাণ গদিতং ময়া ॥ ৫১ ॥
sa-rahasyaṁ tad-aṅgaṁ ca
gṛhāṇa gaditaṁ mayā
“Please hear attentively what I shall speak to you, for transcendental knowledge about Me is not only scientific but also full of mysteries.
Transcendental knowledge of Śrī Kṛṣṇa is deeper than the impersonal knowledge of Brahman, for it includes knowledge of not only His form and personality but also everything else related to Him. There is nothing in existence not related to Śrī Kṛṣṇa. In a sense, there is nothing but Śrī Kṛṣṇa, and yet nothing is Śrī Kṛṣṇa save and except His primeval personality. This knowledge constitutes a complete transcendental science, and Viṣṇu wanted to give Brahmājī full knowledge about that science. The mystery of this knowledge culminates in personal attachment to the Lord, with a resulting effect of detachment from anything “non-Kṛṣṇa.” There are nine alternative transcendental means of attaining this stage: hearing, chanting, remembering, serving the lotus feet of the Lord, worshiping, praying, assisting, fraternizing with the Lord, and sacrificing everything for Him. These are different parts of the same devotional service, which is full of transcendental mystery. The Lord said to Brahmā that since He was pleased with him, by His grace the mystery was being revealed.