तँ होवाच यथा सोम्य महतोऽभ्या-हितस्यैकमङ्गारं खद्योतमात्रं परिशिष्टंतं तृणैरुपसमाधाय प्राज्वलयेत्तेन ततोऽपि बहु दहेत् ॥ ५ ॥
In plain words
He said to him: 'My dear, take a great fire that has been piled high with fuel, until only a single ember remains, no bigger than a firefly. If you cover it with dry grass and fan it into a flame, that tiny spark will burn far brighter than before.'
Close to the Sanskrit
To him he spoke: Just as, O dear one, of a great piled-up fire, a single ember firefly-sized is left over, having covered that with grasses one should ignite it, by that even more it would burn.