There is a pretty Indian fable to the effect that if it rains when the star Svati is in the ascendant, and a drop of rain falls into an oyster, that drop becomes a pearl. The oysters know this, so they come to the surface when that star shines, and wait to catch the precious raindrop. When a drop falls into them, quickly the oysters close their shells and dive down to the bottom of the sea, there to patiently develop the drop into the pearl. We should be like that. First hear, then understand, and then, leaving all distractions, shut your minds to outside influences, and devote yourselves to developing the truth within you. There is the danger of frittering away your energies by taking up an idea only for its novelty, and then giving it up for another that is newer.
Take one thing up and do it, and see the end of it, and before you have seen the end, do not give it up. He who can become mad with an idea, he alone sees light. Those that only take a nibble here and a nibble there will never attain anything. They may titillate their nerves for a moment, but there it will end. They will be slaves in the hands of nature, and will never get beyond the senses.
Source: The Complete Works of Swami Vivekananda/Volume 1/Raja-Yoga/Pratyahara And Dharana