Bāhiya of the Bark Cloth realizes the Dhamma and attains final Nibbāna immediately after receiving a concise teaching from the Buddha.
Bāhiya sutta - To Bāhiya
Thus have I heard - At one time, the Blessed One was dwelling in Sāvatthi, in Jeta's Grove, Anāthapiṇḍika's park. Now, at that time, Bāhiya of the Bark Cloth was living in Suppāraka, by the seashore. He was honored, respected, revered, worshipped, and esteemed. He was a recipient of the four requisites: robes, alms-food, lodging, and medicines. Then, while Bāhiya was alone in seclusion, the following train of thought arose in his mind: "Whoever in the world are Arahants or have entered the path to Arahantship, I am one of them."
Then, a deity, who was a former blood-relative of Bāhiya of the Bark Cloth, who was compassionate and benevolent towards Bāhiya's welfare, perceiving Bāhiya's train of thought with mind, approached him. Having approached him, the deity said: "Bāhiya, you are neither an Arahant nor have you attained the path to Arahantship. Nor do you even have the way of practice by which you could become an Arahant or attain the path of Arahantship."
"Then who, in the world with its gods, are Arahants or have attained the path to Arahantship?"
"There is, Bāhiya, in the northern country, a city called Sāvatthi. There, at present, dwells the Blessed One, the arahant, the perfectly awakened one. Indeed, Bāhiya, that Blessed One is both an arahant and teaches the Dhamma for the sake of arahantship."
Then, Bāhiya of the Bark Cloth, stirred by that deity, immediately departed from Suppāraka. Traveling with a one-night stay in each place, he went to Sāvatthi, to Jeta's Grove, Anāthapiṇḍika's park. At that time, several bhikkhus were walking back and forth in the open air. Bāhiya approached those bhikkhus, and having approached them, he said: "Venerable sirs, where is the Blessed One, the arahant, the perfectly awakened one, dwelling at present? We wish to see that Blessed One, the arahant, the perfectly awakened one."
The bhikkhus replied: "Bāhiya, the Blessed One has gone among the houses for alms."
Then, Bāhiya of the Bark Cloth, hurrying quickly, left Jeta's Grove and entered Sāvatthi. There, he saw the Blessed One walking on his alms around, graceful and inspiring confidence, calm and with a peaceful mind, having arrived at the highest self-mastery and tranquility, tamed, guarded, restrained in senses — a noble person. After seeing him, Bāhiya approached the Blessed One. Having approached him, he prostrated with his head at the Blessed One's feet and said: "Venerable sir, may the Blessed One teach me the Dhamma! May the Well-Gone One teach me the Dhamma so that it would be for my benefit and happiness for a long time."
When this was said, the Blessed One replied to Bāhiya of the Bark Cloth: "Bāhiya, this is an inappropriate time, as we have entered among the houses for alms."
For a second time, Bāhiya of the Bark Cloth said to the Blessed One: "Venerable sir, it is difficult to know the danger to the Blessed One's life, or to the danger to my life. May the Blessed One teach me the Dhamma! May the Well-Gone One teach me the Dhamma so that it would be for my benefit and happiness for a long time."
For a second time, the Blessed One replied to Bāhiya of the Bark Cloth: "Bāhiya, this is an inappropriate time, as we have entered among the houses for alms."
For a third time, Bāhiya of the Bark Cloth said to the Blessed One: "Venerable sir, it is difficult to know the danger to the Blessed One's life, or to the danger to my life. May the Blessed One teach me the Dhamma! May the Well-Gone One teach me the Dhamma so that it would be for my benefit and happiness for a long time."
"In that case, Bāhiya, you should train thus:
'In what is seen, there will merely be the seen, In what is heard, there will merely be the heard, In what is sensed, there will merely be the sensed, In what is cognized, there will merely be the cognized.'
In this way, Bāhiya, you should train. When for you, Bāhiya, in what is seen, there will merely be the seen, in what is heard, there will merely be the heard, in what is sensed, there will merely be the sensed, in what is cognized, there will merely be the cognized, then, Bāhiya, you will not be 'by that.' When you are not 'by that,' then, Bāhiya, you will not be 'in that.' When you are not 'in that,' then, Bāhiya, you will be neither here, nor there, nor in-between the two. Just this is the end of suffering."
Then, through the Blessed One's concise teaching of the Dhamma, Bāhiya of the Bark Cloth's mind was immediately liberated from the defilements, without any clinging remaining.
After giving this concise advise to Bāhiya of the Bark Cloth, the Blessed One departed. Soon after the Blessed One had left, a cow with a young calf charged at Bāhiya of the Bark Cloth and killed him.
Then the Blessed One, having walked for alms in Sāvatthi, after the meal, while returning from alms round from the city together with several bhikkhus, saw Bāhiya of the Bark Cloth lying dead. Having seen, he addressed the bhikkhus: "Bhikkhus, take Bāhiya of the Bark Cloth's dead body, place it on a cot, carry it away, and cremate it. Then make a stupa for him. Bhikkhus, your spiritual companion has died."
"Yes, venerable sir," the bhikkhus replied to the Blessed One. Having replied in agreement, they took Bāhiya of the Bark Cloth's dead body, placed it on a cot, carried it away, cremated it, and made a stupa for him. Then they approached the Blessed One. Having approached the Blessed One, they paid homage to him and sat down to one side. Having sat down to one side, the bhikkhus said to the Blessed One: "Venerable sir, Bāhiya of the Bark Cloth's dead body has been burned, and a stupa has been made for him. What is his trajectory? What is his future existence?"
The Blessed One replied: "Bhikkhus, Bāhiya of the Bark Cloth was wise. He practiced in accordance with the teaching and did not impede me with the technical points of the teaching. Bhikkhus, Bāhiya of the Bark Cloth has attained final Nibbāna."
Then, understanding the significance of this, the Blessed One at that time expressed this inspired utterance:
"Where water, earth, fire and wind find no footing; Where the stars do not shine, the sun does not manifest; The moon does not illuminate, And yet there, darkness is not found.
When the sage, the brahmin, realizes this for himself through silence; Then he is freed from both form and formless [existences], and from pleasure and pain."