Why did he say "Hemah Yeni'un Le'echol"?
Rashi: This is like dogs; they go around the entire night looking for food, if they are not satiated. If they are satiated, they sleep.
Radak: Even though they go around to houses to beg for food, they will not be satiated.
Malbim: Now they will go around like a hungry dog looking for food. It barks amidst its hunger.
Why does it say "Im Lo Yisba'u"?
Radak #1: Im is like 'in truth', like "v'Im Beriyah Yivra Hashem" (Bamidbar 16:30) and similar verses.
Radak #2: Im is like Ka'asher, like "v'Im Yihyeh ha'Yovel" (Bamidbar 36:4). They will go around to get food, and spend the night when they are not satiated.
Malbim: If they are hungry, then they go around to seek food, [so they will be able to sleep at night.
Why does it say "va'Yalinu"?
Radak: They will spend the night hungry. The prefix Vov is like Ka'asher. The same applies to "v'Sifsei Renanos Yehalel Pi" (63:6).
