Meaning “On attaining the great reservoir ,full on all sides , serves the same purpose of water filled in small pits. Similarly all the purposes of veda can only be understood by the one ,who knows the purpose behind it.” ExplanationKrishna is indicating thatthe purpose of all the vedas is like the availability of reservoir full on all side becomes recessive in front of the sea ,where there is no dearth of water and it is everywhere. Graduate yourself in wisdom to attain the true self and advance in the spiritual consciousness. The sum total of vedic studies is knowing the true self and is equivalent to any activity ,that is mentioned in the vedas.