In plain words
He told them to teach him the matter that causes bondage. That is, he said, they must hand over to him all the attraction of the world. He told them to teach him the secrets of family life. His intention was that he would then leave the spiritual and enter this material path of worldly bondage. By the king's command, these Caṇḍāmarkas taught him in many ways. But Prahlāda was not moved in any way. No change of any kind took place. Without loosening the hold he had taken, he stood firm in one and the same feeling of the Ātma. That was Prahlāda's vow.
Whatever he held, he held it fast, and did not go till his hold had won; whatever he asked, he asked and asked, and did not let go till it was given; whatever he thought, he thought it through, and did not move till the thought was fulfilled; whatever he wished, he wished it truly, and kept on worshipping till the wish was granted. Unable to bear the strife, He Himself must protect, or I, unaware of my body, must go to Him; turning back is no vow of a devotee.
Prahlāda's was not a heart that wavers every moment, like today's students, like today's devotees. Prahlāda's was an unwavering gaze, an unwavering Manas. Caring nothing for hardships, losses or sorrows, never letting go of the name of Hari, he kept up his contemplation of God, ceaselessly, in Ānanda. This sight filled even the Caṇḍāmarkas with wonder. They came to the emperor.
When the night-roamers stab him, the Daitya's son, again and again, 'O You who rest on the serpent! O Destroyer of demons! O Lord of the world! O Refuge of those in great distress! O Purifier of all!' so he praises; yet he sheds no tears from his eyes, nor trembles with fear, O King!