Thence-forth residing in the house of the preceptor the boy Prahlāda, whenever he got an opportunity, gave lessons himself to the sons of the Dānavas. Prahlāda said,—"O sons of the descendants of Diti, hear from me the supreme truth; do not take my instruction otherwise for there is no touch of covetousness. All creatures are born first, then they attain to infancy and youth and then succeed gradually the inevitable decay; and then they meet with death, O sons of the Daitya chiefs.

In plain words: Back at his teacher's house, Prahlada secretly teaches the other demon boys whenever he can. He tells them he wants nothing from them. He reminds them that every creature is born, grows up, grows old, and then dies.