Krishna loves us, although we have become indifferent to reciprocate His unrequited love. So, the flute helps Krishna send a very sweet love letter, a warm invitation letter in the form of transcendental sound vibration. He is calling us. If not for attracting us, Krishna wouldn’t have bothered to play His flute.
Krishna doesn’t like to revel in His own glories but He desires to relish loving exchanges with His dear devotees. This is the nature of Rasa. He is simply inviting us, who are too much engrossed in enjoying this material world that is full of suffering, to join His eternal pastimes.
Those who have acknowledged His love letter have never returned to the material world. Having gone mad, they are dancing in rapture. Only those who have turned a deaf ear are struggling perpetually in the cycle of birth and death.
mām upetya punar janma duḥkhālayam aśāśvatam
nāpnuvanti mahātmānaḥ saṁsiddhiṁ paramāṁ gatāḥAfter attaining Me, the great souls, who are yogīs in devotion, never return to this temporary world, which is full of miseries, because they have attained the highest perfection.- Bhagavad Gita 8.15