The katha of Bahula the cow
In Braj, among Shri Krishna's cows, there was a cow named Bahula who was dear to everyone. One day, while grazing, she got separated from the herd and wandered far into the forest.
Suddenly a lion appeared before her, ready to eat her. Bahula pleaded, 'My little calf is hungry at home. Let me go and feed him one last time, then I will come back to you myself.'
The lion said, 'What is the guarantee you will come back?' Bahula swore by truth and dharma. The lion let her go.
Bahula went home, fed her calf, loved him, and returned to the forest to keep her word. Seeing her truthfulness, the lion took his real form — it was Shri Krishna himself, testing Bahula.
Shri Krishna said, 'Bahula, I am pleased with your truthfulness. From today you will be worshipped on Bhadrapad Krishna Chaturthi, and the children of mothers who keep this vrat will be happy.'
This is OmKiran Bhakti's retelling of the traditional katha in simple English; details of the katha vary slightly from region to region.