The Old Covenant made at Sinai must be understood against the backdrop of what a covenant fundamentally is: a formal, binding contract specifying parties, terms, and consequences, sealed and witnessed, carrying penalties for noncompliance and rewards for faithfulness. Hebrews 8 reveals that this covenant was flawed not because of God, whose word is always sure, but because of the people—Israel lacked what it took to fulfill their part. This covenant builds upon the earlier Abrahamic covenant, in which God's primary requirement of Abraham was simply to "walk before Me and be blameless"—a relationship based on faith and trust, with obedience following as a natural result. Circumcision, given in Genesis 17, served as the sign of that covenant, marking those set apart to God. Notably, circumcision is essentially absent from the Old Covenant itself, mentioned only in passing regarding childbirth regulations and twice regarding "circumcision of the heart," showing that even within the Pentateuch, God was already pointing toward inward transformation rather than mere physical marking. The Abrahamic and Old Covenants, made with the same people, eventually became intertwined, so that circumcision came to be regarded as a sign of the law of Moses. In Exodus 19, God lays out the prelude to the Old Covenant: if Israel would obey His voice and keep His covenant, they would become His special treasure, a kingdom of priests, and a holy nation—a model people meant to demonstrate God's ways to the rest of the earth. The people eagerly agreed, likely drawn by the promise of exaltation "above all peoples," yet Psalm 78 exposes the tragic reality: they were a stubborn and rebellious generation whose hearts were not set aright and whose spirit was unfaithful. Despite witnessing extraordinary miracles, they forgot God's works entirely. Even the terrifying display of divine power at Sinai, meant to instill reverent fear and help them avoid sin, failed to produce lasting devotion; instead, they diminished God in their minds, treating Him as no greater than themselves. The Ten Commandments, functioning as the preamble to this covenant, were not new laws invented at Sinai but eternal principles reflecting God's own unchanging character, already in force since creation and equally foundational to the New Covenant, where they are written on hearts rather than stone. The subsequent judgments and ordinances (Exodus 20:22-23:19) governed daily communal life, while God's promises—protection, provision, healing, fertility, and expanded territory—formed His side of the bargain, conditioned on Israel's obedience and separation from foreign gods. Contrary to claims that God's law is impossible to keep, the covenant's design shows it was meant to be kept faithfully, even if not perfectly, through right heart and motivation. The Israelites' failure stemmed not from an unreasonable demand but from human nature's inherent hostility to God, a condition only remedied by the Spirit. The covenant was formally ratified with blood in Exodus 24, sealing Israel's calling to become a holy, priestly nation—yet within days that same nation was bowing before a golden calf, setting the stage for the recurring cycle of obedience and apostasy that would ultimately lead to their downfall.

God specifically designated Israel a sanctified people, setting the entire nation apart from the world's nations and giving it responsibilities to perform before them as a testimony of obedient service (Deuteronomy 7:6). Declaring some things clean and others unclean defined this holiness. Gentiles were unclean not by nature but because of their idolatry, so intermarriage was forbidden except within narrow limits. Because Israel was holy, its ceremonial duties had to be performed exactly as God specified, since each detail serves His purposes with His people. A holy people must give holy offerings, meaning offerings given according to His stated details. Nothing could be offered from a foreigner's hand, because the foreigner's corruption is in it (Leviticus 22:25), and a firstfruits offering had to come from what Israel itself had sown (Exodus 23:16). Grain sown by Canaanites therefore could not serve as a wavesheaf. Israel's holiness also meant undivided loyalty to God and national unity around one central sanctuary and altar (Deuteronomy 12), with no syncretism and no additions or subtractions to His commands. Even the conquest was to be carried out by a circumcised people, and Christ, the true First of the Firstfruits, was born into this holy people.