Rashi: The quiver that holds arrows. Radak - since the children are [metaphorically] called arrows, the house is called a quiver. Malbim - just like arrows do not help if he cannot shoot them at the target, so children help only if they are "Mehem" (good arrows, i.e. for Hashem).

Rashi: Chachamim who defeat each other in Halachah, and appear like enemies. Kidushin 30b - even a father and son, or a Rebbi and Talmid, when they engage in Torah, they become enemies. "Es v'Hav b'Sufah" (Bamidbar 21:14) - in the Sof (end), they will love each other. Radak - the father and son will not be embarrassed when they talk in front of Chachamim.