Śrī Kṛṣṇa's form, Śrī Kṛṣṇa's flute, Kṛṣṇa's color—everything is reality.
(Srimad Bhagavatam----10:2:35----purport).

The gopīs declared, "To see Lord Kṛṣṇa playing His flute while taking the cows to pasture is the highest perfection for the eyes. What pious activities has this flute performed that enable him to freely drink the nectar of Śrī Kṛṣṇa's lips-a blessing we cowherd girls find difficult to achieve?
(Srimad Bhagavatam----10:21--summary).

Hearing the song of Kṛṣṇa's flute, the peacocks dance, and all the other creatures become stunned when they see them. Demigoddesses traveling through the sky in their airplanes are vexed by Cupid, and their garments become loose. The ears of the cows stand on end as they drink the nectar of this flute-song, and their calves simply stand stunned, the milk they have been drinking from their mothers' udders still in their mouths.
(Srimad Bhagavatam----10:21--summary).

The birds take shelter of the branches of the trees and close their eyes, listening to the song of Kṛṣṇa's flute with rapt attention.
(Srimad Bhagavatam----10:21--summary).

Some of the gopīs were milking cows when they heard Kṛṣṇa's flute. They stopped milking and went off to meet Him. Some left milk curdling on the stove, and others left cakes burning in the oven.
(Srimad Bhagavatam----10:29:5----translation).

When the gopīs hear Kṛṣṇa playing His flute as He leaves Vraja in the morning with His cows or returns with them at sunset, the young girls quickly come out of their houses to see Him. They must have performed many pious activities to be able to see Him as He walks on the road, His smiling face mercifully glancing upon them.
(Srimad Bhagavatam----10:44:16----translation).

The flute of Kṛṣṇa`s pastimes measures three fingers in length, and it is bedecked with indranīla gems. At the ends of the flute are aruṇa gems (rubies), glittering beautifully, and between its ends the flute is plated with gold set ablaze by diamonds. This auspicious flute, pleasing to Kṛṣṇa, is glittering in His hand with transcendental brilliance.
(Sri Caitanya Caritamrta----3:1:161----purport).

When the transcendental sound of Kṛṣṇa's flute is heard, the devotee's anxiety to continue to hear that flute enables him to penetrate the covering of the material world and enter into the spiritual sky, where the transcendental sound of the flute enters into the ears of the followers of the gopīs.
(Teachings of Lord Caitanya).

The sound of Kṛṣṇa's flute always resides within the ears of the gopīs and increases their ecstasy.
(Teachings of Lord Caitanya).

In Brahma-saṁhitā a nice description of the flute of Kṛṣṇa is given: "When Kṛṣṇa began to play on His flute, the sound vibration entered into the ear of Brahmā as the Vedic mantra oṁ" This oṁ is composed of three letters—A, U, and M—and it describes our relationship with the Supreme Lord, our activities by which we can achieve the highest perfection of love and the actual position of love on the spiritual platform.
(Teachings of Lord Caitanya).

When the sound vibration of Kṛṣṇa's flute is expressed through the mouth of Brahmā, it becomes gāyatrī. Thus by being influenced by the sound vibration of Kṛṣṇa's flute, Brahmā, the supreme creature and first living entity of this material world, was initiated as a brāhmaṇa. That Brahmā was initiated as a brāhmaṇa by theflute of Kṛṣṇa is confirmed by Śrīla Jīva Gosvāmī.
(Teachings of Lord Caitanya).

When Brahmā was enlightened by the gāyatrī mantra through Kṛṣṇa's flute, he attained all Vedic knowledge.
(Teachings of Lord Caitanya).

In the Tenth Canto, Thirty-fifth Chapter, verse 15, of Śrīmad-Bhāgavatam, the gopīs tell mother Yaśodā, "When your son plays on His flute, Lord Śiva, Lord Brahmā and Indra—although they are supposed to be the greatest learned scholars and personalities—all become bewildered. Although they are all very great personalities, by hearing the sound ofKṛṣṇa's flute they humbly bow down and become grave from studying the sound vibrated."
(Nectar of Devotion).

In his book Vidagdha-mādhava, Śrī Rūpa Gosvāmī thus describes the vibration of Kṛṣṇa's flute: "The sound vibration created by the flute of Kṛṣṇa wonderfully stopped Lord Śiva from playing his ḍiṇḍima drum, and the same flute has caused great sages like the four Kumāras to become disturbed in their meditation. It has caused Lord Brahmā, who was sitting on the lotus flower for the creative function, to become astonished. And Anantadeva, who was calmly holding all the planets on His hood, was moving in this way and that due to the transcendental vibration from Kṛṣṇa's flute, which penetrated through the covering of this universe and reached to the spiritual sky."
(Nectar of Devotion).

There are three kinds of flutes used by Kṛṣṇa. One is called veṇu, one is called muralī, and the third is called vaṁśī. Veṇu is very small, not more than six inches long, with six holes for whistling. Muralī is about eighteen inches long with a hole at the end and four holes on the body of the flute. This kind of flute produces a very enchanting sound. The vaṁśī flute is about fifteen inches long, with nine holes on its body. Kṛṣṇa used to play on these three flutes occasionally when they were needed. Kṛṣṇa has a longer vaṁśī, which is called mahānandā, or sammohinī. When it is still longer it is called ākarṣiṇī. When it is even longer it is called ānandinī. The ānandinī flute is very pleasing to the cowherd boys and is technically named vaṁśulī. These flutes were sometimes bedecked with jewels. Sometimes they were made of marble and sometimes of hollow bamboo. When the flute is made of jewels it is called sammohinī. When made of gold, it is called ākarṣiṇī.
(Nectar of Devotion).

It is described that by hearing the vibration of Kṛṣṇa's flute, Lord Śiva becomes very puzzled and begins to cry so loudly into space that the demons become vanquished and the devotees become overwhelmed with joy.
(Nectar of Devotion).

Moist existential ecstatic love aroused in connection with Kṛṣṇa is divided into two: direct and indirect. Rādhārāṇī was weaving a garland of kunda flowers, and upon hearing the vibration of Kṛṣṇa's flute, She immediately stopped Her work.
(Nectar of Devotion).

Similarly, one gopī said to another, "My dear friend, when I heard the sound of Kṛṣṇa's flute, I tried to hide myself from the reaction of the vibrations. But still I could not check the trembling of my body, and therefore all of my friends in the house could detect my attachment for Kṛṣṇa without any doubt."
(Nectar of Devotion).

The gopīs' sleeping condition is compared to the white swans, and the sound of Kṛṣṇa's flute is compared to a black wasp. When Kṛṣṇa's flute sounded, the white swans, which represent the sleeping condition of the gopīs, were immediately vanquished, and the black wasp sound of the flute began to enjoy the lotus flower of the gopīs' beauty.
(Nectar of Devotion).

Once the cowherd boys in Vṛndāvana were vainly searching after Kṛṣṇa for a long time, and for that reason their faces became blackened, and their complexions appeared faded. Just then they could hear on the hill a faint vibration from Kṛṣṇa's flute. Immediately all of them became very much gladdened.
(Nectar of Devotion).

Sometimes the vibration of Lord Kṛṣṇa's flute, His bugling, His smiling, His footmarks on the ground, the transcendental fragrance of His body and the appearance of a new cloud in the sky also become impetuses for ecstatic love of Him.
(Nectar of Devotion).

In the Vidagdha-mādhava there is the following statement: "When Kṛṣṇa was playing on His flute, Baladeva very anxiously declared, 'Just see how, after hearing the transcendental sound of Kṛṣṇa's flute, Indra, the King of heaven, is crying in his heavenly kingdom! And from his teardrops falling on the ground, Vṛndāvana appears to have become a celestial residence for the demigods.' "
(Nectar of Devotion).

According to Vedic astronomical calculation, if there is rain during the constellation of the Svātī star, any rain falling on the sea will produce pearls, and rain falling on a serpent will produce jewels. Similarly, when Kṛṣṇa's flute roared like a thundercloud under the Svātī constellation, the resulting perspiration on Śrīdāmā's body appeared to be just like pearls.
(Nectar of Devotion).

The parental love of mother Yaśodā for Kṛṣṇa steadily increases, and her love and ecstasy are sometimes described as intense affection and sometimes as overwhelming attachment. An example of attachment for Kṛṣṇa with overwhelming affection is given in Śrīmad-Bhāgavatam, Tenth Canto, Sixth Chapter, verse 43, where Śukadeva Gosvāmī addresses Mahārāja Parīkṣit in this way: "My dear King, when magnanimous Nanda Mahārāja returned from Mathurā, he began to smell the head of his son, and he was merged in the ecstasy of parental love." A similar statement is there in connection with mother Yaśodā when she was too anxious to hear the sound of Kṛṣṇa's flute, expecting Him back from the pasturing ground. Because she thought that it was getting very late, her anxiety to hear the sound of Kṛṣṇa's flute became doubled, and milk began to flow from her breast.
(Nectar of Devotion).

In the Padyāvalī of Rūpa Gosvāmī it is stated that when the gopīs hear the sound of Kṛṣṇa's flute, they immediately forget all rebukes offered by the elderly members of their families. They forget their defamation and the harsh behavior of their husbands. Their only thought is to go out in search of Kṛṣṇa. When the gopīs meet Kṛṣṇa, the display of their exchanging glances as well as their joking and laughing behavior is called anubhāva, or subecstasy in conjugal love.
(Nectar of Devotion).

In the Lalita-mādhava, Rūpa Gosvāmī explains that the movements of Kṛṣṇa's eyebrows are just like the Yamunā and that the smiling of Rādhārāṇī is just like the moonshine. When the Yamunā and the moonshine come in contact on the bank of the river, the water tastes just like nectar, and drinking it gives great satisfaction. It is as cooling as piles of snow. Similarly, in the Padyāvalī, one constant companion of Rādhārāṇī says, "My dear moon-faced Rādhārāṇī, Your whole body appears very content, yet there are signs of tears in Your eyes. Your speech is faltering, and Your chest is also heaving. By all these signs I can understand that You must have heard the blowing of Kṛṣṇa's flute, and as a result of this, Your heart is now melting."
(Nectar of Devotion).

After hearing the vibration of the flute of Kṛṣṇa, the gopīs in Vṛndāvana remembered Him and began to talk amongst themselves about how nicely Kṛṣṇa was playing His flute.
(Krsna Book).

Another gopī said, "My dear friends, Kṛṣṇa is so nicely dressed that He appears to be the impetus to various kinds of ceremonies held by the womenfolk. Even the wives of the denizens of heaven become attracted after hearing the transcendental sound of His flute. Although they are traveling in the air in their airplanes, enjoying the company of their husbands, on hearing the sound of Kṛṣṇa's flute, they immediately become perturbed. Their hair is loosened, and their tight belts are slackened." This means that the transcendental sound of the flute of Kṛṣṇa extended to all corners of the universe. Also, it is significant that the gopīs knew about the different kinds of airplanes flying in the sky.
(Krsna Book).

Another gopī said to her friends, "My dear friends, the cows are also charmed as soon as they hear the transcendental sound of the flute of Kṛṣṇa. It sounds to them like the pouring of nectar, and they immediately spread their long ears just to catch the liquid nectar of the flute. As for the calves, they are seen with the nipples of their mothers pressed in their mouths, but they cannot suck the milk. They remain struck with devotion, and tears glide down from their eyes, illustrating vividly how they are embracing Kṛṣṇa heart to heart."
(Krsna Book).