1)
Why did he say "v'Lo b'Hachris Hashem Es Oyvei David"?
1.
Rashi: Your Chesed should not cease also when my father's house is punished. I know that Hashem will cut off your enemies!
2.
Radak: Even when Hashem eradicates all of your enemies, and not one remains, do not eradicate my house, even though my father's family was among your enemies. Malbim - you are bound by a Shevu'ah about this!
