Karpas is a little bit of food with a lot of metaphors.  We take a newly-grown thing and dip it into saltwater, which is said to represent tears. Water is central to the Exodus story: not just the tears but the river, the sea which parts. It represents phase changes -- in this case from lost to found, as with Moshe who Yocheved set off on the river. Moshe's river journey parallels the Pharoh's mandate that all Hebrew children should be drowned in that same river.

Who was tasked with this awful mandate? Shifra and Puah, non-Hebrew midwives. According to the story, they simply refused to comply. And when they were confronted about how they didn't do it, they lied. As non-enslaved people, these midwives took huge risks to thwart a law that didn't even apply to them, and so their names will always be remembered for bringing new growth forth from the tears.

haggadah Section: Karpas