Adhyātma-dīpam means... Just like ātmā, the soul, is within this body, but due to our darkness knowledge, insufficient knowledge, we cannot understand ātmā, Paramātmā. We cannot understand. So in the darkness, as you require a torchlight, similarly, Śrīmad-Bhāgavatam is just like the torchlight. You can see ātmā and Paramātmā. Adhyātma-dīpam. Dīpam means light, lamp. So why it is required? Atititīrṣatām. Just like light is required by a person who wants to go through the darkness but go to the light. Suppose here is light and there is tunnel, and in the tunnel you require some light, to go to the other part of the light. Similarly, this world, this material world, is full of darkness. That is the difference between material world and spiritual world. Material world means darkness wherein you cannot understand what is God, what you are. That is material world.
They are very busy in this material world, but they do not know where they are going. Andhā yathāndhair upanīyamānāḥ [SB 7.5.31]. Actually, they are darkness. The material world is darkness. The so-called scholars and teachers, they are also in the darkness, and they are leading other people in the darkness. Because it is darkness, therefore we require sunshine, moonshine and this electricity. As soon as it is covered, the sun is covered, you can experience it is darkness. At night it is darkness. Actually, it is darkness. But by the grace of Kṛṣṇa, He has arranged the light. But there is another world where there is no need of, na tad bhāsayate sūryo na śaśāṅko na pāvakaḥ [Bg. 15.6]. There is another world where there is no need of these things lighting agent, either sunshine or moonshine. But God is so kind that in each and every universe, it is full of darkness. Now, you see how brilliant sun is there. This is His kindness. Yasya prabhā prabhavato jagad-aṇḍa-koṭiḥ [Bs. 5.40]. Yac-cakṣur eṣa savitā sakala-grahāṇām. Therefore the sun is described as the eye of all the planets. Because you have got very nice good planet, very nice city, Rome and London and America, this and that. That's all right. But as soon as it is dark, you cannot see anything. The mercy of sunshine, Kṛṣṇa's mercy, is there. Therefore you can see. You can enjoy.
Prabhupada's lecture - Śrīmad-Bhāgavatam 1.2.3 - Rome, May 27, 1974