One day the god Brahma wanted to test the divinity and power of Krishna, the eighth avatar of Vishnu.
The young god had gone with his friends to bring grazing calves.
Arrived on the banks of river Yamuna, boys started playing when they realized that the animals had disappeared into the forest. Krishna assured his companions and went in search of animals.
The research, however, did not lead to anything, Krishna could not find the animals which had been kidnapped by Brahma.
Returned on the banks of the Yamuna, Krishna was even more amazed, because his friends were gone, they too had been the god Brahma.
Thanks to his own divinity and powers, Krishna realized what had happened, Brahma was putting him to the test.
The young god knew that Brahma would surely have given back children and calves to their homes, but there was a 'but', that is, that one moment of Brahma corresponds to a year for men, and therefore, even if the joke the god would certainly have been short, for men would last too.
Worried about the anxiety and pain that would affect the inhabitants of Vrndavana, thanks to his own divine powers, Krishna multiplied himself and took the forms, features, appearances, personalities of all the disappeared boys and all the calves too.
Being now evening, Krishna brought his friends and calves in their homes and no one noticed that those kids and those calves were nothing but Krishna, as in nothing they were different from boys and calves who were kidnapped by Brahma.
So when after a moment (divine) Brahma brought back the boys and calves in Vrndavana, a year had passed (human), but no one had noticed anything.