"You are the greatest among the monkeys," Jambavan said to Hanuman, "but you have forgotten your powers. Your father is Vayu the wind-god, and you can fly as high and as far as you want, just like the wind. As a baby, you flew into the sky to grasp the sun. The gods have bestowed blessings upon you."
Hanuman stared at Jambavan in surprise.
"You must remember who you are!" Jambavan told him. "Then you will be able to make this leap to Lanka to find Sita and to learn how Rama might rescue her. You must jump, Hanuman: jump!"
Inspired by: Valmiki's Ramayana
Notes: This is from Book 4: Kishkindha Kanda, sarga 66. Jambavan does not tell Hanuman about how he lost his self-knowledge but you can read a story about that here: Hanuman's Curse.