Ramayana
यदा तु शास्त्राण्यध्येतुं शक्तिरस्य भविष्यति । तदास्य शास्त्रं दास्यामि येन वाग्ग्मी भविष्यति ॥ 7-36-14 ॥
And when he gains the capacity to study the scriptures, then I shall impart the scripture to him, whereby he shall become eloquent.
english translation