1)
Why does it say "Avar" (singular)? "Mayim" is plural!
1.
Radak #1: We find like this - "Mei Nidah Lo Zurak Alav" (Bamidbar 19:13).
2.
Radak #2: Avar refers to Nachal mentioned in the previous verse.
2)
What is "ha'Zeidonim"?
1.
Radak: They flood with evil and intent.
2.
Malbim: This is a metaphor for denial of fundamentals of our creed. This refers back to "Lulei Hashem she'Hayah Lanu" (1, 2). Had we forgotten His name, they would have eradicated our Nefesh via denial of our creed.
