yathaa nadeenaam bahavombuvegaahaa samudramevaabhimukhaa dravanti |
tathaa tavaamee naralokaveeraa vishanti vaktraanyabhivijvalanti || 28 ||

Like torrents of several rivers rush towards the ocean, so do those brave men of this earth run to your blazing mouths.
yathaa : like
nadeenaam : rivers
bahavaha : several
ambuvegaahaa : torrents
samudram : ocean
eva : only
abhimukhaa : towards
dravanti : rush
tathaa : so do
tava : to you
amee : those
naralokaveeraa : brave men of the earth
vishanti : run
vaktraani : mouths
abhivijvalanti : blazing
Putumayo, Caqueta, Vaupes, Guainea, Morona, Pastaza, Nucuray, Urituyacu, Chambira, Tigre, Nanay, Napo, and Huallaga. These are names of just a handful of 1100 rivers that feed the Amazon, the largest river in the world by volume. It covers almost 7 million square kilometres of land in South America, and empties 300,000 cubic metres per second into the Atlantic Ocean. The most distant source of the Andes is a glacier on the western edge of South America, near the Pacific Ocean, on the other side of the continent.
Arjuna, on seeing the hordes of warriors rushing into Ishvara’s mouths, compares them to the water in a river rushing with great speed into the ocean. It reminds him of Shri Krishna’s description of the water cycle as a sacrifice when he was explaining karma yoga. A drop of water which originated from the ocean evaporates into the sky, falls down as rain into a water body, and eventually finds its way into a flowing river that goes right back into its source, the ocean. At one point it thinks that it is rain, or it is a pond, a lake, a stream and so on, forgetting its true nature as water.
Similarly, we tend to think of ourselves as children, students, engineers, executives, rich people, poor people at different points in our lives, and forgetting that our journey is just a cycle that begins from Ishvara, the source, and ends back into that same source. So even though Arjuna was scared of Ishvara’s monstrous form, he understood that there was nothing to be scared about destruction. It was a bona fide part of Ishvara’s creative process.
Arjuna illustrates another aspect of this scene in the next shloka.