That is stated in the Bhagavad-gītā: mat-sthāni sarva-bhūtani na cāhaṁ teṣv avasthitaḥ (BG 9.4). Although you do not find Kṛṣṇa in somewhere, but His energy is acting there. So one who has eyes to see how Kṛṣṇa's energy is acting, he sees Kṛṣṇa. Same example: because the prime minister's energy is working in that office, so the prime minister is there present.
So everything is demonstration of the energy. Just like you are in the room, you have not seen the sun, but as soon as the sunshine is there, you know that sun is there. You see the sun through the sunshine, although it is not that sun has come into your room. The sunshine, coming of the sunshine within your room, is sufficient knowledge to know that here is sun, sun is there. That is the Vedic statement, that you can understand there is fire when there is heat. If there is light and heat, then you can understand there is fire. That heat and light is sufficient. Now, what is the heat and light? This is energy of the fire.
So when Kṛṣṇa says in the Bhagavad-gītā, "These material elements," bhūmir āpo 'nalo vāyuḥ (BG 7.4), "earth, water, fire, air, they are My energies," so if one has studied Kṛṣṇa, then as soon as He sees a great ocean, He sees Kṛṣṇa: "Oh, this is Kṛṣṇa's energy." As soon as sees a big anything, fire, water, anything, He sees Kṛṣṇa, nothing but Kṛṣṇa, because He knows. Exactly in the same way, as soon as you feel heat, you know that there is fire. You don't require to see the fire. But if you feel, "Oh, it is hot. Oh, there must be fire." This is studying Kṛṣṇa. And this is called Kṛṣṇa consciousness: to feel the presence of Kṛṣṇa everywhere.
So everything requires training, undergoing the process. Then it is possible. It is not impossible. So if you also go, the training, the process, you'll also understand. It is not difficult.