Arañña Jātaka (No.348)
The Bodhisatta was once born in a brahmin family. He learned all the arts in Takkasilā, but when his wife died he went with his son to be an ascetic in the Himavā. One day a girl came to the hermitage, fleeing from brigands, and corrupted the virtue of the youth. However, when she tried to induce him to go away with her, he wished to consult his father. The father warned him against leaving the hermitage and taught him the way to mystic meditation (J.iii.147‑9).
The reason for telling the story is given in the Cūḷanārada Jātaka.