Rashi explains that with water they thought to destroy them, and they themselves were destroyed by water.
Why was Yisro worthy of having an entire parsha of the Torah named after him? What distinguished him to deserve the remarkable honor accorded him? There were men who undoubtedly were aware of Pharaoh’s terrible decree to drown the Jewish baby boys. However, it was only Yisro who was able to take two unrelated events and link them together to see their apparent relationship. He saw the punishment of “measure for measure” in Hashem’s reaction to Pharaoh’s sins. This is the distinction between a ordinary person and one who is great. Man’s greatness is not measured by the amount of knowledge that he possesses. The criteria for greatness is man’s comprehension and subsequent application of this storehouse of knowledge. It is necessary to understand the various historical events that occur and view them in their proper perspective. One who uses proper insight, will clearly see the hand of Hashem as He constantly guides the world.