What are the connotations of "Vechishav im Koneihu"?
Rashi (in Pasuk 48) and Seforno: In spite of the fact that the Pasuk is speaking about a Nochri who is under our jurisdiction, one is obligated to make an accurate assessment of how much the Eved Ivri owes his master and not force him to release his Eved free of charge or for less than the full amount owing. 1
Refer to 25:48:151:1 & 2 and see Torah Temimah, note 263.
Why does the Torah insert the (otherwise superfluous) words "Vechishav Im Koneihu"?
Kidushin, 17b #1: To teach us that someone who is sold to a Nochri serves only the Nochri, but not his heirs in the event that he dies before the Yovel. 1
Kidushin, 17b #2: Refer to 25:50:1.1:1. The inference teaches us that a Nochri has heirs ? and that consequenly his son inherits him. 2
What are the connotations of "ki'Yemei Sachir Yih'yeh Imo"?
Rashi: It means that one reckons how much he paid, and divides it by the number of years until the Yovel. 1 If they then redeem him before the Yovel, they deduct the value of years that he worked, and return the balance to the Nochri.
Rashi: If for example, the Nochri purchased him for twenty Manah, twenty years before the Yovel - then he purchased each year for one Manah, like a hired worker. If they now come to redeem him after five years, they deduct five Manah and pay the Nochri fifteen.