"The Lord sanctified the River Yamuna from the beginning of His transcendental pastimes in the world. While His father Vasudeva was crossing the Yamuna with the baby Lord Krishna for a safe place at Gokula on the other bank of the river from Mathura, the Lord fell down in the river, and by the dust of His lotus feet the river at once became sanctified. It is especially mentioned herein that Maharaja Parikshit took shelter of that particular river which is beautifully flowing, carrying the dust of the lotus feet of Lord Krishna, mixed with tulasi leaves. Lord Krishna's lotus feet are always besmeared with the tulasi leaves, and thus as soon as His lotus feet contact the water of the Ganges and the Yamuna, the rivers become at once sanctified. The Lord, however, contacted the River Yamuna more than the Ganges. According to the Varaha Purana, as quoted by Srila Jiva Gosvami, there is no difference between the water of the Ganges and the Yamuna, but when the water of the Ganges is sanctified one hundred times, it is called the Yamuna."
(Srimad-Bhagavatam 1.19.6, Purport)
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