Why does it say "Asher Nolad Lo"?
Malbim: We find (21) that he had sons from Bas Machir whose lineage was not attributed to him, rather, to Menasheh. The sons listed here were attributed to him. Also, he had sons born after his death (24); these were born in his lifetime.
Why does it say "Es"? This precedes the object of a verb!
Malbim: This comes to include his grandsons. He 'fathered' them with and via his sons. Grandsons are like sons.
Who is "Keluvi"?
Radak: It is Kalev ben Chetzron, like it says below (18). 'Rashi' - in Shmuel I, 25:3 it says [about Naval] "v'Hu Kalbi"; the Targum is mid'Veis Kalev. He boasted that he has the best lineage in the Shevet. If Shmuel gave kingship to [David], it will come to me. This is why he said "Mi David u'Mi Ven Yishai" - he comes from Rus ha'Mo'aviyah, and [Ram's] brother Yerachmi'el married a Nochris (26) (Yerushalmi Sanhedrin 2:3)!
