ya ātmāntar-yāmī puruṣa iti so 'syāṁśa-vibhavaḥ
ṣaḍ-aiśvaryaiḥ pūrṇo ya iha bhagavān sa svayam ayaṁ
na caitanyāt krṣṇāj jagati para-tattvaṁ param iha
yat-that which; advaitam-without a second; brahma-the impersonal Brahman; upaniṣadi-in the Upaniṣads; tat-that; api-certainly; asya-His; tanu-bhā-the effulgence of His transcendental body; yaḥ-who; ātmā-the Supersoul; antaḥ-yāmī-indwelling Lord; puruṣaḥ-the supreme enjoyer; iti-thus; saḥ-He; asya-His; aṁśa-vibhavaḥ-expansion of a plenary portion; ṣaṭ-aiśvaryaiḥ-with the six opulences; pūrṇaḥ-full; yaḥ-who; iha-here; bhagavān-the Supreme Personality of Godhead; saḥ-He; svayam-Himself; ayam-this one; na-not; caitanyāt-than Lord Caitanya; kṛṣṇāt-than Lord Kṛṣṇa; jagati-in the world; para-higher; tattvam-truth; param-another; iha-here.
What the Upaniṣads describe as the impersonal Brahman is but the effulgence of His body, and the Lord known as the Supersoul is but His localized plenary portion. He is the Supreme Personality of Godhead, Kṛṣṇa Himself, full with six opulences. He is the Absolute Truth, and no other truth is greater than or equal to Him.
The Personality of Godhead is the complete form of sac-cid-ānanda (full life, knowledge and bliss). By realization of the sat portion of the Complete Whole (unlimited existence), one realizes the impersonal Brahman of the Lord. By realization of the cit portion of the Complete Whole (unlimited knowledge), one can realize the localized aspect of the Lord, Paramātmā. But neither of these partial realizations of the Complete Whole can help one realize ānanda, or complete bliss. Without such realization of ānanda, knowledge of the Absolute Truth is incomplete.