Bratharou swarasampanou Gandharvaaviva rupinou
Rupalakshanasampanou Madhuraswarabhashinou
Bimbadivoththithou Bimbou Ramadehath thathaparou
Those texts written by sages are called aarshagranthas. SrimadRamayanam, Srimadbhagavatham,Mahabharatham are all aarshagranthas. Sages accumulate a lot of punyas( merits) during their lifetime.But they choose to gain wisdom and prefer the route towards moksha.Thus they do not enjoy the fruit of their merits.Hence they give all the phala ( fruit) of their punyas to those who read their texts. This is the reason why it is auspicious to read or hear the content of the arshagranthas. Sri Valmiki’s phalasruthi is “ Vishnoho balam pravardhatham”- Let this text give increased strength to the Almighty Vishnu”.Sri Rama too listened to the music of Kusa Lava ( Ramayana was set to music by Valmiki Himself). Thus He accepted Valmiki’s phalasruthi.
When sage Valmiki was composing the Ramayana Lava and Kusa stayed at Valmiki’s ashram, why they were even born at the ashram and being brought by Valmiki Himself. Lava and Kusa were bestowed with great sangeetha gnana. Some are blessed with sangeetha gnanam but their voices are crude. For some it is viceversa. They have beautiful voices but no gnanam. But Lava and Kusa were bestowed with both great sangeetha gnanam and wonderful voices. Their form resembled that of Gandharvas- beautiful and handsome. Jatabharam on their head, broad chest, rounded hands, the bark of a tree on their waists, veena in their hands- their appearance would be ecstatic. They resembled exactly Sri Rama. They were mirror like reflections of Lord Rama. Thus Valmiki chose Lava and Kusa as the apt reservoirs of Srimad Ramayanam.