If everything is filled with water, you will no longer pursue small rewards.

For a person standing in a place where water overflows on all sides, a small well or reservoir is hardly necessary. Section 46 uses this metaphor to illustrate the relationship between a person who is filled by God and the rewards promised by individual rituals.

This is not a denial that the Vedas are unnecessary. The person who ultimately realizes the truth to which the Vedas lead has already overcome the desire for partial and worldly rewards. When one is filled with the whole, there is no need to pursue small amounts of water successively.

Japanese Translation from the Geeta Press Edition - Chapter 2, Section 46: "Before a great flood, small wells are unnecessary."

In the previous section, it was stated that the Vedas deal only with the manifestations of the three gunas. The Lord instructed Arjuna to be free from attachment to all worldly pleasures and their means arising from the three gunas.

Now, let us see the glory of divine realization that arises from such detachment.

Sanskrit original text

यावानर्थ उदपाने सर्वतः सम्प्लुतोदके ।
तावान्सर्वेषु वेदेषु ब्राह्मणस्य विजानतः ॥ ४६ ॥

Romanization

yāvān artha udapāne sarvataḥ samplutodake |
tāvān sarveṣu vedeṣu brāhmaṇasya vijānataḥ || 46 ||

For a liberated Brahmana, all the Vedas are of no more use than a small reservoir is to someone standing on the banks of an ocean that stretches in all directions. (46)

By this analogy, the speaker describes the state of fulfillment possessed by a realized being. A person standing on the shore of a lake that is sweet, life-giving, healthy, and filled with immeasurable water does not need small ponds or wells. This is because all their needs related to water are fulfilled by the water in that lake.

Similarly, those who have realized the divine by renouncing all attachments to objects of pleasure, in other words, those who have attained the highest bliss, which is God or the complete Brahman, do not depend on worldly pleasures for their happiness and satisfaction, as these are rewards obtained through Vedic rituals.

Their desires are fulfilled through dissolution, becoming eternally satisfied without thirst. Therefore, to reach this state, one must completely renounce all desires and attachments to worldly pleasures that are obtained as a result of Vedic rituals, and become completely free from the influence of the three gunas.

This passage can also be interpreted in another way. That is, just as a person standing on the banks of abundant water uses only the necessary amount of water, a wise person who knows Brahman uses the Vedas to the extent that it serves their purpose. However, the interpretation we have adopted here conveys a better meaning. This is because, for a wise person who has realized Brahman, the world itself becomes completely useless (III.18).