Conceptually, these two verses must be read together to understand the logical impact Benjamin desired. To move to a new covenant with Christ, Benjamin must justify superceding the accepted covenant represented by the Mosaic law. To do this, he duly notes that the law of Moses is from God, but that it is a law given because of the stiffneckedness of the people. The unstated but clear conclusion is that this is some type of lesser law, one that might be superceded, particularly were there a people prepared for a greater covenant. In this one verse, Benjamin both sets up the possibility of the new covenant, and relates that new covenant to the ability of the people to accept it (highlighting his theme of his people who have chosen to follow him, and God, and to cast out the contentions).
He then clearly lays out the limitations of the law of Moses. While the Mosaic covenant is important, even that covenant depends upon the atonement of the Savior. Benjamin purposefully uses the atoning image of the blood of Christ here. The purpose is multiple, with possible attachments to the Mesoamerican conceptions of blood sacrifice noted above, but very specifically to the blood sacrifices of the Mosaic law.
The law of Moses is not without its ritual atonement. The Israelite day of Atonement was “the great day of national humiliation, and the only one commanded in the Mosaic law. The mode of its observance is described in Leviticus 16” (Smith, William. “Atonement, The day of.” In: Smith’s Bible Dictionary. Fleming H. Revell Co.. 1970, p. 61). In addition to the well known practice of transferring sin to goats (the origin of the term “scape-goat”) the ceremonies of atonement prominently feature blood sacrifice:
“[The priest] next sacrificed the young bullock as a sin-offering for himself and his family. Taking with him some of the blood of the bullock, he filled a censer with burning coals from the brazen altar, took a handful of incense, and entered into the most holy place. He then threw the incense upon the coals and enveloped the mercy-seat in a cloud of smoke. Then, dipping his finger into the blood, he sprinkled it seven times before the mercy-seat eastward. The goat upon which the lot ”For Jehovah" had fallen was then slain and the high priest sprinkled its blood before the mercy-seat in the same manner as he had done that of the bullock. Going out from the Holy of Holies he purified the holy place, sprinkling some of the blood of both the victims on the altar of incense. (Smith, 1970, p. 61).
“Hebrews 13:10-13 clearly equates the sin offering of Ex. 29:10-14 with the atonement of Jesus – including the casting out of the ”scapegoat“ (”Complete Text of Benjamin’s Speech with Notes and Comments." In: King Benjamin’s Speech. FARMS 1998, p. 554).
Since the timing of the day of Atonement was five days prior to the Feast of the Tabernacles, the conceptions of blood and atonement would have been reasonably fresh in the minds of a Mosaic law-abiding people, even though their ceremony would have some differences from the description above (due to differences in time and location – not to mention the difficulty in coming up with bulls and goats). The part of this for Benjamin’s discourse is that blood is associated with atonement, both in the law of Moses, and in the promise of the Redeeming Messiah.
What Benjamin has done, in a deft and swift stroke, is to equate the sacrificial blood of the day of Atonement under the law of Moses with the future atoning blood of Christ. For Benjamin, they are the same blood, and it is that future blood of Christ that makes efficacious the ritual blood of the sacrificial animal under the law of Moses. Thus Christ not only supercedes the law of Moses, but is the foundation upon which the law of Moses has its atoning power.