From the Bhagavata Purana
After a little while, Rama and Keshava began to play in the village, crawling on their hands and knees. They slithered about quickly, dragging their feet in the muddy pastures, delighting in the tinkling sound. They would follow someone and then, suddenly bewildered and frightened, they would hasten back to their mothers. Their mothers' breasts would flow with milk out of tenderness for their own sons, whose bodies were beautifully covered with mud, and they would embrace them in their arms and give them their breasts to stick, and as they gazed at the faces with their innocent smiles and tiny teeth they would rejoice. Then the children began to play in the village at those boyish games that women love to see. They would grab hold of the tails of calves and be dragged back and forth in the pastures and the women would look at them and forget their housework and laugh merrily. But the mothers, trying to keep the two very active and playful little boys from horned animals, fire, animals with teeth and tusks, and knives, water, birds, and thorns, were unable to do their housework, and they were rather uneasy.
After a little while, Rama and Krishna stopped crawling, on their hands and knees and began to walk about the pastures quickly on their feet. Then the lord Krishna began to play with Rama and with the village boys of their age, giving great pleasure to the village women. When the wives of the cowherds saw the charming boyish pranks of Krishna, they would go in a group to tell his mother, saying, "Krishna unties the calves when it is not the proper time, and lie laughs at everyone's angry shouts. He devises ways to steal and eat curds and milk and thinks food sweet only if lie steals it. He distributes the food among the monkeys; if lie doesn't eat the food, he breaks the pot. If he cannot find anything, he becomes angry at the house and makes the children cry before lie runs away. If something is beyond his reach, he fashions some expedient by piling up pillows, mortars, and so on; or if lie knows that the milk and curds have been placed in pots suspended in netting, he makes holes in the pots. When the wives of the cowherds are busy with household duties, he will steal things in a dark room, making his own body with its masses of jewels serve as a lamp. This is the sort of impudent act which he commits; and he pees and so forth in clean houses. These are the thieving tricks that he contrives, but he behaves in the opposite way and is good when you are near." When his mother heard this report from the women who were looking at Krishna's frightened eyes and beautiful face, she laughed and did not wish to scold him.
One day when Rama and the other little sons of the cowherds were playing, they reported to his mother, "Krishna has eaten dirt." Yasoda took Krishna by the hand and scolded him, for his own good, and she said to him, seeing that his eyes were bewildered with fear, "Naughty boy, why have you secretly eaten dirt? These boys, your friends, and your elder brother say so." Krishna said, "Mother, I have not eaten. They are all lying. If you think they speak the truth, look at my mouth yourselfIf that is the case, then open your mouth," she said to the lord Hari [Vishnu], the god of unchallenged sovereignty who had in sport taken the form of a human child, and he opened his mouth.
She then saw in his mouth the whole eternal universe, and heaven, and the regions of the sky, and the orb of the earth with its mountains, islands, and oceans; she saw the wind, and lightning, and the moon and stars, and the zodiac; and water and fire and air and space itself; she saw the vacillating senses, the mind, the elements, and the three strands of matter. She saw within the body of her son, in his gaping mouth, the whole universe in all its variety, with all the forms of life and time and nature and action and hopes, and her own village, and herself. Then she became afraid and confused, thinking, "Is this a dream or an illusion wrought by a god? Or is it a delusion of my own perception? Or is it some portent of the natural powers of this little boy, my son? I bow down to the feet of the god, whose nature cannot be imagined or grasped by mind, heart, acts, or speech; he in whom all of this universe is inherent, impossible to fathom. The god is my refuge, he through whose power of delusion there arise in me such false beliefs as "I", "This is my husband", "This is my son", "I am the wife of the village chieftain and all his wealth is mine, including these cowherds and their wives and their wealth of cattle."
When the cowherd's wife had come to understand the true essence in this way, the lord spread his magic illusion in the form of maternal affection. Instantly the cowherd's wife lost her memory of what had occurred and took her son on her lap. She was as she had been before, her heart flooded with even greater love. She considered Hari [Vishnu]--whose greatness is extolled by the three Vedas and the Upanisads and the philosophies of Sankhya and yoga and all the Satvata texts--she considered him to be her son.