You cannot understand Kṛṣṇa by any other process—by jñāna, by yoga, by tapasya, by karma, by sacrifice, by charity. You cannot understand. Simply, Kṛṣṇa says, bhaktyā mām abhijānāti. If you want to know Kṛṣṇa as He is, then you have to take to this process, very simple process, man-manā bhava mad-bhakto mad-yājī māṁ namaskuru (BG 18.65): "Always think of Me, become My devotee, worship Me and offer your respectful obeisances unto Me." Four things. That is here. Chant Hare Kṛṣṇa. That will be thinking of Kṛṣṇa, man-manā. And unless you are devotee, you cannot engage your time in that way. Then if you chant Hare Kṛṣṇa mahā-mantra, automatically you become devotee. Then you worship Deity. Unless you are a devotee, you cannot worship Kṛṣṇa.
The atheist will say, "They are worshiping some idol." No. That is not fact. They do not know that here is Kṛṣṇa personally; He is accepting the devotees' service in a manner in which we can serve Him at the present moment. If Kṛṣṇa shows you the virāṭ-rūpa, then you cannot serve Him. Where you'll get the dress of the virāṭ-rūpa? The whole world's cloth factory will fail you. (laughter) Therefore Kṛṣṇa is accepted, a four-feet-small Deity, so that you can acquire Kṛṣṇa's dress within your means. You can put Kṛṣṇa within your means. That is Kṛṣṇa's mercy. Therefore it is forbidden, arcye viṣṇu śilā-dhīḥ (Padyāvalī 115). If any rascal thinks that in the Viṣṇu form, as stone, as wood; vaiṣṇave jāti-buddhiḥ, devotees considered as belonging to certain nation, caste—these are nārakī-buddhi. (break) This is not to be done. It is fact that here is Kṛṣṇa. Very kindly, just to show me favor, He has come in this form. But He's Kṛṣṇa; He's not stone. Even it is stone, that is also Kṛṣṇa, because there is nothing else but Kṛṣṇa, anything. Without Kṛṣṇa, there is no existence. Sarvaṁ khalv idam brahma (Chāndogya Upaniṣad 3.14.1). So Kṛṣṇa has got the power that even in His so-called shape of stone, He can accept your service. That is Kṛṣṇa.