From the very beginning of time, God has only ever had one way of saving people: by His grace, through our faith (Ephesians 2:8-9). While the dynamic expression of the covenants and the daily practice of the salvation experience progressed throughout history, the underlying mechanism of salvation has never changed.
The Bible makes it clear that no human being has ever been saved by being "good enough" or by perfectly keeping religious rules, because we all fall short of God’s perfect standard (Romans 3:23). Whether someone lived thousands of years before Jesus or lives today, salvation is a free gift from God that must be received by trusting in His promises.
We see this truth illustrated at the very dawn of humanity. When Adam and Eve sinned, they immediately recognized their nakedness and tried to cover up their own shame with makeshift fig leaves (Genesis 3:7). But their human effort was entirely insufficient. It was God who graciously stepped in, rejecting their human coverings and instead clothing them with animal skins (Genesis 3:21). This first sacrifice was a powerful prophetic picture showing that we cannot save ourselves or cover our own spiritual nakedness; only God can provide us with salvation.
While God's grace has always been the saving mechanism throughout history, the only difference is the believer's perspective in time: Old Testament believers were saved by looking forward in faith to the Messiah God promised to send (Genesis 3:15), while New Testament believers are saved by looking backward in faith to what Jesus actually accomplished.
In Romans 4:2-3, the Bible points to Abraham—who lived long before the Law of Moses existed—and says he was saved simply because he "believed God, and it was counted to him as righteousness." To make the standard of pure faith airtight, the Apostle Paul emphasizes that Abraham received this status of righteousness before he was circumcised (Romans 4:10). This proves that external rituals do not save. Abraham was the heir of the promise that originally started with Adam and Eve. His faith was directly connected to that same promise when God told him the Savior would come through his specific lineage as the ultimate, singular "Seed" (Genesis 22:18, Galatians 3:16).
The Law of Moses was not a ladder to earn salvation; rather, it was a grace given to a chosen people who were already redeemed from Egypt by God's power, completely apart from their own righteousness (Deuteronomy 9:6). God delivered Israel out of bondage by grace first (Exodus 20:2), and then gave them His Law to govern their new lives. The Moral Law (the Ten Commandments) revealed God's unchanging holy standard and exposed the people's ongoing structural need for a Savior (Galatians 3:24). The Ceremonial Law (the sacrificial system) provided a gracious pathway for cleansing and forgiveness when the people inevitably broke the moral law, maintaining their horizontal fellowship with the community and vertical fellowship in His holy presence (Leviticus 26:11-12).
The animal sacrifices of the Old Testament could not permanently remove someone's sin or cleanse their guilt from their conscience; as Hebrews 10:4 says, it is impossible for the blood of bulls and goats to take away sins. Instead, those sacrifices were anticipatory and ceremonial. They were meant for the purifying of the flesh to keep the people bodily sanctified to come into His presence (Hebrews 9:13). Crucially, these offerings gave the people a daily understanding of their sin and their deep need for true forgiveness, pointing them forward to Jesus.
The rituals didn't save their souls from an eternal perspective, but they did produce temporal blessings or curses, life or death, dependent upon the nation's obedience (Deuteronomy 30:19). They safely managed Israel's daily fellowship with God and pointed forward to the coming Savior who would completely deal with sin and evil once and for all (Hebrews 9:26). Even in the Old Covenant, the rituals were useless without a transformed heart; the people were always required to walk them out by faith and not by mere natural effort (Habakkuk 2:4).
Disclaimer: These are not my exact words but have been put together at my direction from my personal biblical studies.