Halakhah for Kiddushin 47:13

The commandment of work with a Canaanite slave forever: That we have a Canaanite slave work forever, meaning that we should never manumit him; and he should only go free for [suffering the loss of] a tooth or limb, as it appears in Scripture (Exodus 21:26-27) - or from the main limbs that are similar to them, meaning limbs that do not grow back, as the accepted traditional explanation comes about this (Kiddushin 24a) - as it is stated (Leviticus 25:46) "you shall work them forever." And they, may their memory be blessed, said (Gittin 38a), "Rav Yehudah said, 'Anyone who manumits his slave is in violation of a positive commandment, as it says, "you shall work them forever."'" And [any] one from all of the [other] nations who was acquired by a Jew as a slave is called a Canaanite slave. But all slaves are attached with the name, Canaan, because Canaan was cursed to be a slave - he and his progeny - forever. And even though this section in which we were commanded to subjugate them is speaking about Canaanites - as it is written (Leviticus 25:44), "from the peoples that surround you may you purchase a slave or maid-servant," and it is written earlier (Leviticus 25:38), "to give to you the Land of Canaan" - it was known to the Sages, may their memory be blessed, that it was not only Canaan and those in their land that were called Canaanite slaves. As the law is the same for all the rest of the nations - that they have the status of a Canaanite slave in every matter.

The commandment of the second tithe: To remove the second tithe from the produce in four years of the sabbatical cycle, meaning to say, after we separate the first tithe that is given to the Levites, that we separate yet another tithe. And hence it is called the second tithe. And the law of this tithe is that it be eaten in Jerusalem. And about it is it stated (Deuteronomy 14:22), "You shall surely tithe the produce of your seed." And Scripture elucidates that if the place is far from us and we cannot carry it there except with great burden and much expense, that we can redeem it and bring up its value [to] Jerusalem and spend it there only for the needs of eating and drinking. And Scripture likewise elucidates that the one who redeems his tithe needs to add a fifth to the value - which is to say that if it was worth four dinar, that he eat instead of it [that which costs him] five dinar in Jerusalem. And about this is it stated (Leviticus 27:31), "And if a man surely redeems from his tithe, he shall add its fifth to it." And they, may their memory be blessed, made a precise inference (Kiddushin 24a): "'From his tithe - but not from the tithe of his fellow; 'a man from his tithe' - but not a woman."