Prabhupāda: What do you mean, "understanding"? Simply hear hear and get out from the other.
Devotee: But I mean . . . (indistinct) . . . we can't understand Kṛṣṇa with our mind.
Prabhupāda: With your material mind. When you are Kṛṣṇa consciousness, your quality of mind is changed. The mind . . . the understanding of God is simply purification of the senses. Ataḥ śrī-kṛṣṇa-nāmadi na bhaved grāhyam indriyaiḥ (CC Madhya 17.136). By the present senses you cannot understand what is God, what is His name, what is His quality, what is His form, what are activities. You have to learn this. The Bhagavad-gītā says vetti tattvataḥ. You have to learn.
So now, as you say, that mind . . . of course, with this mind you cannot understand. You cannot think of Kṛṣṇa. With this tongue you cannot chant Hare Kṛṣṇa. With these ears you cannot hear what is Hare Kṛṣṇa. With these eyes you cannot see what is Kṛṣṇa. But if you purify . . . just like cataractic eyes cannot see, but if you purify the eyes, then you can see everything. The eyes will remain as it is, but you have to purify. The process is purification. Sevonmukhe hi jihvādau (CC Madhya 17.136). That purification takes place when you engage yourself in the service of Kṛṣṇa.
So this Kṛṣṇa consciousness movement means to engage a person in the service of Kṛṣṇa. Just like the temple is Kṛṣṇa's. You wipe out the floors, you decorate it, collect flowers, engage your eyes to hear about Kṛṣṇa, engage your tongue for chanting Hare Kṛṣṇa. So engage your eyes to see the Deity, engage your legs to go to the temple. In this way, if you engage your senses, present senses for Kṛṣṇa consciousness, then it becomes gradually purified and you . . . Kṛṣṇa becomes revealed. Sevonmukhe hi jihvādau svayam eva.