It is interesting that Limhi apparently assumed that in return for being delivered out of bondage by his "brethren who were in the land of Zarahemla," his people in the land of Lehi-Nephi would become "their slaves" (Mosiah 7:14-15) One might ask, Was slavery part of Nephite culture?
In Alma 27:9, Ammon credits his father Mosiah2 with establishing a law forbidding slavery: "It is against the law of our brethren, which was established by my father, that there should be any slaves among them . . ." Thus, at least by the reign of Mosiah2 slavery had been legally eliminated. Did slavery exist during the reign of king Benjamin? All we find is that Benjamin did not condone slavery. In his farewell address, Benjamin notes that "Neither have I suffered . . . that ye should make slaves one of another." (Mosiah 2:13) Considering the power of kingship ("your wish is my command"), one might assume that Benjamin also established a policy of non-slavery. However, John Sorenson notes the possibility that perhaps Benjamin forbade the making of new slaves but permitted the institution to continue where it already existed. (Sorenson, Nephite Culture and Society, p. 235.) Whatever the case, if Zeniff and his people departed the land of Zarahemla during the reign of Mosiah1, it is possible that they carried with them the practice of slavery under certain conditions and circumstances.
With these ideas of slavery in mind, it is interesting that John Tvedtnes supports the idea that the speech of king Benjamin and the coronation of king Mosiah2 took place at the festival of Sukkot ("booths" or "tabernacles"). (John A. Tvedtnes, "King Benjamin and the Feast of Tabernacles," in Lundquist and Ricks, eds., By Study and Also by Faith, 2:197-237.) More importantly, Tvedtnes mentions John Welch's argument that Benjamin's speech took place during a jubilee year and claims that this is consistent with a Feast of Tabernacles setting because the jubilee year is announced in the same seventh month that this festival occurs. So one might ask, Why is a jubilee year associated with the Feast of Tabernacles so significant? and What does this have to do with slavery and returning to the Nephite land of Zarahemla?
According to Jennifer Lane, the jubilee year (and possibly sabbatical years) would have been a very significant setting for King Benjamin to give a message about spiritual redemption because it was the time when Israelite slaves were to be freed (Deuteronomy 15:12-18; Leviticus 25:39-42) and people were freed from their debts (Deuteronomy 15:1-3), and it is only in the jubilee year that the land is returned to its original owners (Leviticus 25:25-28). [Jennifer Clark Lane, "The Lord Will Redeem His People: Adoptive Covenant and Redemption in the Old Testament and Book of Mormon," in Journal of Book of Mormon Studies, Vol. 2/2, Fall 1993, pp. 49-50]
It is also worth noting that the very next day ("on the morrow") after king Limhi made his remark about slavery ("it is better that we be slaves to the Nephites than to pay tribute to the king of the Lamanites"--see Mosiah 7:15), he brought his people to the temple to announce a formal message of redemption from bondage:
if ye will turn to the Lord with full purpose of heart, and put your trust in him, and serve him with all diligence of mind, if ye do this, he will, according to his own will and pleasure, deliver you out of bondage. (Mosiah 7:33)
It is also noteworthy that immediately after king Limhi addressed his people, Ammon reinforced Limhi's message of redemption from bondage with the teachings of king Benjamin (at the jubilee year Feast of Tabernacles): "he rehearsed unto them the last words which king Benjamin had taught them, and explained them to the people of king Limhi, so that they might understand all the words which he spake." (Mosiah 8:3) [Alan C. Miner, Personal Notes]