1)
What are "Beki'ei Ir David"?
1.
Rashi: The cracks in the wall - "you saw that they increased." Radak - Ir David is Tziyon.
2)
What is the meaning of "va'Tekabetzu Es Mei ha'Rechev"?
1.
Targum Yonasan: You gathered the nation to the water of the lower pond. Rashi - it is near the cracks in the wall of Ir David. You gathered them for war, for you saw the weak spot of Yerushalayim there; it is easy to conquer from there.
2.
Radak, Malbim: The pond water was scattering to leave; you gathered it inside, so the water will be prepared to make mortar to seal the breaches. Brechah is a cavity built in rocks to gather rainwater.
