With these words from the OT, God codified and formalized the means whereby the sacrifice of innocent animals takes place as a vicarious payment for sin, payment rightly owed by sinners. In the Torah, there were several related motives for performing sacrific­es. Central were the ideas of propitiation, expiation, and reconciliation. “Atonement” is the word coined to explain a state of reconcilia­tion achieved by covering over or appeasing the justified wrath of a wronged party, usually by a payment in the form of a sacrifice. Atonement (originally “atonement”) is an inclusive noun incorporating three related Biblical ideas central to the restoration of a positive, friendly relationship with God. Let’s now take a necessarily brief look at these ideas.

Propitiation means the appeasement or satisfaction of an offended party. Imagine the anger of a person wronged by another – one party in a relationship steals from the other, or lies, or betrays trust or in some way dishonours the other. Imagine the anger felt by the injured party. If any hope of repairing the relationship exists, the righteous anger of the injured party must in some commensurate way be satisfied or neutralized. Propitiation occurs when the demands for restitution from the injured party are acceded to in some way. Expiation means the compensating payment of a penalty for wrong or harm done. Again in our hypothetical example imagine what the injured party would expect in order to set things right. If lied to, she would expect nothing but truth from then on, if stolen from, she would expect repayment in kind, if betrayed she would demand trust and loyalty. This idea is imperfectly expressed in the law of talion, the legal principle of making the punishment correspond to the crime. In human terms, the ultimate law of talion is life for life. Nevertheless, God has determined, according to His perfect righteousness, that sin is the greatest harm and as such the sinner is worthy of death as the appropriate penalty.

Reconciliation means the return of friendly relations after an estrangement. Think of the estranged people in our previous hypothetical example, one in which a formerly positive relationship, due to the actions of one person, becomes marred or spoiled. The relationship begins to break apart and both parties suffer. Not only that, the separation increases, the relationship worsens until finally there seems no hope of restoration. How often does this happen to married people, let alone good friends? Reconciliation must occur in order for healing to take place. This reconciliation results from acts of propitiation and expiation. We don’t often understand our personal relationships this way, however, this is the process that must take place for those who become estranged after being on intimate terms (Matt. 5:22-24).

Our sin has estranged us from God (Gen. 3:8). Moreover, we – being dead in our sin – are eternally unable to overcome this estrangement and effect reconciliation. If – as the Westminster Larger Catechism declares as our purpose and end – we are to have a right relationship with God, enjoying Him forever, then only He is able – through sovereign grace – to effect that reconciliation.

Our estrangement is the result of our breaking God’s moral law, which is sin. We become aware of sin in this way though, only when we have some standard by which to make a comparison. Now, the breaking of a law implies a prior agreement between two parties to uphold that law. In this case, the agreement – commonly called a covenant – is between mankind and God, with God dictating the terms. These terms (or governing conditions) we know as the moral law, summa­rized in the Ten Commandments. (They were not given to Israel only, on Sinai, but to all mankind and are in universal, permanent effect.) Consequently, if we were able to live by this law perfectly, our positive relationship with God would never have been marred in the first place.

In the law portions of the Torah, this reconciliation – atonement – was provisionally enabled through the rites of animal sacrifice, until the coming of God’s Suffering Servant (Isa. 53:4-6). However, even though these specific regulations of the law were given to God's chosen people as a gift for attaining reconciliation, the Bible tells us these rituals had no permanent effect (Heb. 10:1-4). What was ultimately required then, was a permanent sacrifice of atonement; a sacrifice that was also perfect or complete. In order to bring this about, a new covenant had to be established and this could only be done through a perfect sacrifice, “For if that first covenant had been faultless, there would have been no occasion sought for a second. For finding fault with them, He says, ‘Behold, days are coming, says the LORD, when I will effect a new covenant with the house of Israel and with the house of Judah’” (Heb. 8:7-8). Just how did God determine to reconcile us with Himself in the bonds of a new, permanent covenant? Through the most amazing, unexpected and awe-inspir­ing way imaginable, “For God so loved the world that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life” (John 3:16).

The magnitude of God’s decision is staggering. Knowing as He did that mankind’s sin was overpowering and that we are slaves to our sin with no hope of redemption on our own, He came to us and paid His own penalty, the penalty that only He could pay. The penalty was death, a sacrificial death to propitiate His own wrath and to expiate sin for the last time, and so finally reconciling us to Him. God in the person of the Father sent God in the person of the Son to die on the cross as a sacrifice for the sins of humanity.

Therefore, Jesus became the ultimate and final sin offering; the consummation of a new covenant and a new, reconciled relationship with God through God’s planned and deliber­ate sacrifice of His own Son on the cross of Glory. “Men of Israel, listen to these words: Jesus the Nazarene, a man attested to you by God with miracles and wonders and signs which God performed through Him in your midst, just as you yourselves know – this Man delivered over by the predetermined plan and foreknowledge of God – you nailed to a cross by the hands of godless men and put to death” (Acts 2:22-23).

We see that our Lord made the final and complete payment for sin and this full willingly. His death covers over or cancels all our debts. As well, God imputes the righteousness of His Son to us, not because of our worthiness, not because we are in any way deserving, but simply because God loves us.