I have heard that on one occasion the Blessed One was staying near Savatthi, in Jeta's Grove, Anathapindika's monastery. Now at that time Ven. Nanda — the Blessed One's brother, son of his maternal aunt — told a large number of monks, "I don't enjoy leading the holy life, my friends. I can't endure the holy life. Giving up the training, I will return to the common life."
Then a certain monk went to the Blessed One and, on arrival, having bowed down to him, sat to one side. As he was sitting there, he told the Blessed One: "Lord, Ven. Nanda — the Blessed One's brother, son of his maternal aunt — has told a large number of monks, 'I don't enjoy leading the holy life, my friends. I can't endure the holy life. Giving up the training, I will return to the common life.'"
Then the Blessed One told a certain monk, "Come, monk. In my name, call Nanda, saying, 'The Teacher calls you, my friend.'"
"As you say, lord," the monk answered and, having gone to Ven. Nanda, on arrival he said, "The Teacher calls you, my friend."
"As you say, my friend," Ven. Nanda replied. Then he went to the Blessed One and, on arrival, having bowed down to him, sat to one side. As he was sitting there, the Blessed One said to him, "Is it true, Nanda, that you have told a large number of monks, 'I don't enjoy leading the holy life, my friends. I can't endure the holy life. Giving up the training, I will return to the common life.'?"
"Yes, lord."
"But why, Nanda, don't you enjoy leading the holy life?"
"Lord, as I was leaving home, a Sakyan girl — the envy of the countryside — glanced up at me, with her hair half-combed, and said, 'Hurry back, master.' Recollecting that, I don't enjoy leading the holy life. I can't endure the holy life. Giving up the training, I will return to the common life."
Then, taking Ven. Nanda by the arm — as a strong man might flex his extended arm or extend his flexed arm — the Blessed One disappeared from Jeta's Grove and reappeared among the devas of the Tavatimsa Heaven. Now at that time about 500 dove-footed nymphs had come to wait upon Sakka, the ruler of the devas. And the Blessed One said to Ven. Nanda, "Nanda, do you see those 500 dove-footed nymphs?"
"Yes, lord."
"What do you think, Nanda: Which is lovelier, better looking, more charming — the Sakyan girl, the envy of the countryside, or these 500 dove-footed nymphs?"
"Lord, compared to these 500 dove-footed nymphs, the Sakyan girl, the envy of the countryside, is like a cauterized monkey with its ears and nose cut off. She doesn't count. She's not even a small fraction. There's no comparison. The 500 dove-footed nymphs are lovelier, better looking, more charming."
"Then take joy, Nanda. Take joy! I am your guarantee for getting 500 dove-footed nymphs."
"If the Blessed One is my guarantee for getting 500 dove-footed nymphs, I will enjoy leading the holy life under the Blessed One."
Then, taking Ven. Nanda by the arm — as a strong man might flex his extended arm or extend his flexed arm — the Blessed One disappeared from among the devas of the Tavatimsa Heaven and reappeared in Jeta's Grove. The monks heard, "They say that Ven. Nanda — the Blessed One's brother, son of his maternal aunt — is leading the holy life for the sake of nymphs. They say that the Blessed One is his guarantee for getting 500 dove-footed nymphs."
Then the monks who were friends of Ven. Nanda went around addressing him as they would a hired hand and a dealer: "Our friend Nanda, they say, is a hired hand. Our friend Nanda, they say, is a dealer. He's leading the holy life for the sake of nymphs. The Blessed One is his guarantee for getting 500 dove-footed nymphs."
Then Ven. Nanda — humiliated, ashamed, and disgusted that the monks who were his friends were addressing him as they would a hired hand and a dealer — went to dwell alone, secluded, heedful, ardent, and resolute. He in no long time entered and remained in the supreme goal of the holy life for which clansmen rightly go forth from home into homelessness, knowing and realizing it for himself in the here and now. He knew: "Birth is ended, the holy life fulfilled, the task done. There is nothing further for the sake of this world." And thus Ven. Nanda became another one of the arahants.
— Ud 3.2
Buddha at first shows the reality of impermanence to Ven. Nanda by showing him to the Nymphs. Our moments opinion and perception holds true first only to the present moment and also to us. There is nothing fix and absolute. Buddha instead of preaching to him (as he has resolved to abandon his practise.), he showed him the truth. What we see as absolute now is undergoing fleeting changes. Thus inclining to everchange things are way to suffering.
Next Buddha promised Ven. Nanda to give him the 500 Nymphs. These allow Ven. Nanda to reflect upon thyself his foolish wants. Sometimes advicing or preaching might fall to deaf ears....rather...show them the truth.
In the Lotus Sutra, Buddha also used expedient means to show disciples into the right path. When some one stays in his house and never ventures out. The house is his truth. Only by using ways to get him out of his little comfort zone....he sees hope, he vows and thus leads to salvation.