Kṛṣṇa says in the Bhagavad-gītā that bhaktyā mām abhijānāti (BG 18.55). If you want to understand Kṛṣṇa or if anyone wants to understand Kṛṣṇa perfectly, tattvataḥ, in truth, then he has to understand it through bhakti, not any other process, although there are many other processes, different ways. Some so-called philosophers, they say that "We can adopt any process. It leads to the same goal." That's all right, provided you make progress. Then you'll reach to the same goal. But if you become stuck up with the process only, you do not make progress, then it does not lead to the same goal. Just like one staircase going to the fourth floor. So you cross, say, twenty-five steps. You are in a certain position. If you cross fifty steps, you are in a certain position. If you cross sixty steps . . . In this way, the final may be hundred steps. So unless you go to the hundredth step, the final position is not attained, although it is leading to the same goal. Therefore we have to make progress. From karma-kāṇḍa we have to learn what is the actual position of karma-kāṇḍa, why you are engaged in karma-kāṇḍa. That is called jñāna. Then, coming to the jñāna-kāṇḍa, then you come to the upāsanā-kāṇḍa. Then upāsanā-kāṇḍa, when you reach the highest, topmost upāsanā . . . Upāsanānāṁ sarveṣāṁ viṣṇor ārādhanaṁ param (CC Madhya 11.31, Padma Purana). When you become Vaiṣṇava, when you worship Kṛṣṇa, Viṣṇu, that is the perfectional stage.
So mama vartmānuvartante manuṣyāḥ pārtha sarvaśaḥ (BG 4.11). Everyone is going to the same goal, but he has to make further progress. Don't think, "By karma-kāṇḍa we have come to the final stage," or "By jñāna-kāṇḍa, we can . . ., we have come to the final stage," or "By upāsanā-kāṇḍa, by worshiping demigods, we have come to the final stage." No. The final stage, you can come directly by bhakti, the topmost upāsanā.