The Bible speaks of reconciliation using three principle Greek terms: "katallassō," "katallagē" and "apokatallassō." However in classical Greek usage, these terms are usually used in the context of restoring the original relationship between people after some hostility or displeasure; Greek thought did not use such terms in the context of a personal relationship with God.

The terms: "katallassō," "katallagē" and "apokatallassō" are rarely used in the New Testament.

Katallassō (Strong number: 2644)

This Greek verb means "to change" or "exchange (especially of money)" or "to reconcile." To reconcile is to exchange enmity for friendship, and it usually requires that the cause of enmity or hostility be removed.

Katallagē (Strong number: 2643)

This Greek noun means "reconciliation." Reconciliation is defined as the restoration of a good relationship between enemies.

Apokatallassō (Strong number: 604)

This Greek term is a stronger form of katallassō and means to "reconcile completely." It is a reconciliation that removes all anger and leaves no impediment to unity and peace.

and might reconcile (apokatallassō) them both in one body to God through the cross, by it having put to death the enmity. (Eph 2:16)

and through Him to reconcile (apokatallassō) all things to Himself, having made peace through the blood of His cross; through Him, I say, whether things on earth or things in heaven. And although you were formerly alienated and hostile in mind, engaged in evil deeds, yet He has now reconciled (apokatallassō) you in His fleshly body through death, in order to present you before Him holy and blameless and beyond reproach – if indeed you continue in the faith firmly established and steadfast, and not moved away from the hope of the gospel that you have heard, which was proclaimed in all creation under heaven, and of which I, Paul, was made a minister. (Col 1:20-23)

As seen in the verses above, the rare New Testament terms "katallassō," "katallagē" and "apokatallassō" are found only in the writings of the apostle Paul.

From a human perspective, reconciliation is easily understood in Matthew 5:23-24 where Jesus indicates that an offender needs to go the offended and do something to release the hostility or anger the offended person has against him. In 1 Corinthians 7:11, Paul used the term "katallassō" in speaking of reconciling a marital relationship in which the wife was presumably the offender.

To release the anger of the offended, the offender does something (i.e. apologize, repent, compensate, etc.) so that offended changes his view of the offender from unfriendly to friendly.

However when Paul speaks of reconciling the relationship between human beings and God, it is clearly not the same process as a human being initiating the reconciliation with another human being. So Paul's use of the Greek terms "katallassō," "katallagē" and "apokatallassō" is very different than the typical Greek usage of these terms. What was Paul teaching about the atonement of Jesus Christ?

The very idea of reconciliation is initially brought up in Romans 5:10, and Paul identifies human beings as "enemies" in describing the hostile attitude that unbelievers have towards God. In this relationship, Paul is saying that man is the offender, and God is the offended, and there is a sense of anger and condemnation the Creator has towards His creation.

As Paul continues to speak of katallassō," "katallagē" and "apokatallassō," a different picture of reconciliation emerges from that of the typical Greek which refers to the reconciliation between human beings.

• Reconciliation is the restoration of a divine relationship, and its consequence is eternal life for one's spirit / soul (Rom 5:10; 11:15).
• The means of reconciliation is through a death and elsewhere in the Bible, Paul explains that the atonement of Jesus Christ is in substitution of each and every human being (see the article "Substitution… the basis of atonement").

Objectively the death of Jesus Christ paid God's judicial price for the sins of each human being in full and satisfied God's wrath of judgment.

Subjectively the righteousness of Jesus Christ is imputed upon each Believer and brings each one into God's favor (Col 1:20-23).

• Because the means of reconciliation is through the death of the Son of God, it is apparent that the human offender, by his own efforts, cannot reconcile his relationship with God.
• Because the means of reconciliation is through the death of God's only Son, the cost of reconciliation is born by the offended. The penalty of the offense was paid by another.
• Reconciliation results when the offender simply believes in the work of the Mediator (Rom 11:15; Col 1:20-23). For those who believe in the atonement of Jesus Christ, the sins of the offender is forgiven, and God no longer has any hostility towards the offender. Without such faith, no man can be reconciled with God.
• The reconciliation that results from the atonement of Jesus Christ is so complete that sincere Believers of different ethnicities would have their attitudes changed removing all anger and animosity towards each other and leaving no impediment to unity and peace (Eph 2:16). True reconciliation of human relationships occurs when there is sincere reconciliation with God by all parties.
• So great is His love that God, in His provision and means for reconcilement, gave former offenders the privilege of representing Him (as ambassadors to the King) so that others may hear the good news (2 Cor 5:18-20).

Nowhere in the Bible does it say or imply that God reconciled Himself to man. Man was indeed reconciled to God. In describing the result of Jesus Christ's atonement with human terms for reconciliation, "katallassō," "katallagē" and "apokatallassō," Paul reveals that God's provision for reconciliation goes far beyond and in contrast to human concepts.