Akrura halted the chariot at the bank of the Yamuna so Krsna and Balarama could perform a ritual of purification and drink some water. After the two Lords had gotten back into the chariot, Akrüra took Their permission to bathe in the Yamuna. As he recited Vedic mantras, he was startled to see the two Lords standing in the water. Akrura came out of the river and returned to the chariot where he saw the Lords still sitting. Then he returned to the water to find out if the two figures he had seen there were real or not.

What Akrura saw in the water was four-armed Lord Väsudeva. His complexion was dark blue like a fresh raincloud, He wore yellow garments and He lay on the lap of thousand-hooded Ananta Sesa. Lord Vssudeva was receiving the prayers of perfected beings, celestial serpents and demons, and He was encircled by His personal attendants. Serving Him were His many potencies, such as Sri, Pusti and Ila, while Brahma and other demigods sang His praises. Akrura rejoiced at this vision and, joining his palms in supplication, began to pray to the Supreme Lord in a voice choked with emotion.

A.C. Bhaktivedanta Swami Prabhupada
Srimad-Bhagavatam 10.39 Summary
© A.C. Bhaktivedanta Swami