Sanctification is the act or process of acquiring sanctity, of being made or becoming holy. "Sanctity" is an ancient concept widespread among religions, a property of a thing or person sacred or set apart within the religion, from temple vessels to days of the week, to a human believer who achieves this state. To sanctify is literally "to set apart for special use or purpose", figuratively "to make holy or sacred", and etymologically from the Latin verb sanctificare which in turn is from sanctus "holy" and facere "to make".
In the various branches of Christianity sanctification usually refers to a person becoming holy, with the details differing in different branches.
Anglicans teach that sanctification is a process of changing to become holy. Richard Hooker, an influential Anglican theologian, argued that sanctification is based on works while justification is only by faith.
Calvinist and Evangelical theologians interpret sanctification as the process of being made holy only through the merits and justification of Jesus Christ through the work of the Holy Spirit. Sanctification cannot be attained by any works based process, but only through the works and power of the divine. When a man is unregenerate, it is their essence that sins and does evil. But when a man is justified through Christ, it is no longer the man (in his essence) that sins, but the man is acting outside of his character. In other words, the man is not being himself, he is not being true to who he is.
Eastern Orthodoxy 
Orthodox Christianity teaches the doctrine of theosis, whereby humans take on divine properties. A key scripture supporting this is 2 Peter 1:4. In the 4th century, Athanasius taught that God became Man that Man might become God. Essentially, Man does not become divine, but in Christ can partake of divine nature. This Church's version of salvation restores God's image in man. One such theme is release from mortality caused by desires of the world.
Martin Luther, the founder of Lutheranism, taught in his Large Catechism that Sanctification is only caused by the Holy Spirit through the powerful Word of God. The Holy Spirit uses churches to gather Christians together for the teaching and preaching of the Word of God.
John Wesley, the founder of Methodism, taught what is known as entire sanctification in the holiness movement churches, such as the Church of the Nazarene, the Salvation Army, or Christian perfection in "mainstream" Methodist denominations, such as the United Methodist Church, the Methodist Church of Great Britain. This is the doctrine that by the power of God's sanctifying grace and attention upon the means of grace may cleanse a Christian of the corrupting influence of original sin in this life. It is explained in depth in the essay, "Entire Sanctification" by Adam Clarke as well as, later, in Articles of Religion in the Book of Discipline of the Methodist Church. "Initial salvation" is sometimes seen as an initial step of acknowledging God's holiness, with sanctification as, through the grace and power of God, entering into it. A key scripture is Hebrews 12:14: "Follow after...holiness, without which no one shall see the Lord."
United Methodists believe that sanctifying grace draws one toward the gift of Christian perfection, which Wesley described as a heart "habitually filled with the love of God and neighbor" and as "having the mind of Christ and walking as he walked".
Roman Catholicism 
According to the Catholic encyclopedia "sanctity" differs for God, individual, and corporate body. For God, it is God's unique absolute moral perfection. For the individual, it is a close union with God and the resulting moral perfection. It is essentially of God, by a divine gift. For a society, it is the ability to produce and secure holiness in its members, who display a real, not merely nominal, holiness. The Church's holiness is beyond human power, beyond natural power.
Sanctity is regulated by standards.
Other Christian denominations and movements 
Beliefs about sanctification vary amongst the Christian denominations and movement, influenced by various Christian movements. These beliefs differ from each other on: whether sanctification is a definitive experience or process, when the process/experience takes place, and if entire sanctification is possible in this life.
Influenced by the Holiness movement some Pentecostal churches, such as the Church of God in Christ and the Apostolic Faith Church, believe that sanctification is a definitive act of God’s grace and spiritual experience whereby we are made holy subsequent to salvation and prior to the baptism of the Holy Spirit. Reformed Churches are amongst denominations that teach about definitive sanctification at the time of conversion, and believers are required to "do good works" which are "… all sanctified by (God’s) grace". Similarly, non-Wesleysan Pentecostals such as Assemblies of God teach about definitive sanctification at the time of conversion and progressive sanctification after conversion. Converted believers are expected to "make every effort to live a holy life… Even though Christians may not attain absolute perfection in this life." The event of entire sanctification occurs when Christ comes back and gives us glorified bodies.
Higher Life movement and Brunstad Christian Church believe that sinless perfection is attainable in Christian life. Even though believers still have an inclination to sin after conversion, they must constantly rely on the Holy Spirit to struggle against this tendency, and therefore can attain sinless perfection in this life. Higher Life movement teaches "the secret of complete victory is faith: simply believing that Jesus has done and is doing all". Brunstad Christian Church focuses on the belief that Jesus was a man during His days on earth. They teach that believers ought to follow him by destroying the sinful nature and thereby increase in divine nature, through the process of "becoming holy as He is holy".
Church of Jesus Christ of Latter-day Saints 
In the Church of Jesus Christ of Latter-day Saints sanctification is a process that makes its members holier. In the scriptural cannon of The Church of Jesus Christ of Latter-day Saints sanctification is mentioned in the following scriptures: Doctrine & Covenants 20:31, "We know also, that sanctification through the grace of our Lord and Savior Jesus Christ is just and true, to all those who love and serve God with all their mights, minds, and strength", and Helaman 3:35, "Nevertheless they did fast and pray oft, and did wax stronger and stronger in their humility, and firmer and firmer in the faith of Christ, unto the filling their souls with joy and consolation, yea, even to the purifying and the sanctification of their hearts, which sanctification cometh because of their yielding their hearts unto God." Dallin H. Oaks, an LDS General authority and member of the Quorum of the Twelve Apostles, taught that trials and adversities can change who a member is into what God wants them "to become" if they approach them with the right attitude.
See also 
- The Mitzvah of sanctifying the Kohen
- Divine Grace
- Imparted righteousness
- Justification (theology)
- Means of Grace
- Perfection (Latter Day Saints)
- Social Gospel
- Gibbs, Lee W. "Richard Hooker's Via Media Doctrine of Justification ." The Harvard Theological Review 74, no. 2 (1981): 211-220. http://www.jstor.org/stable/1509447 (accessed June 10, 2010).
- Dane says:. "Sanctification â€“ A Calvinist Viewpoint | Calvinism | Sanctification â€“ A Calvinist Viewpoint". Learntheology.com. Retrieved 2012-08-04.
- Gerhard O. Forde, Donald L. Alexander, Sinclair B. Ferguson: "Christian spirituality: five views of sanctification", InterVarsity Press, 1988. p. 47-76
- Athanasius: "On the Incarnation", Crestwood: Saint Vladimir's Seminary Press, 1989. p.93
- Robert V. Rakestraw: "On Becoming God: An Evangelical Doctrine of Theosis," Journal of Evangelical Theological Society 40/2 (June 1997) 257-269
- Veli-Matti Karkkainen: "One With God: Salvation as Deification and Justification," Collegeville: Liturgical Press, 2004. p.18
- Lutheran Dogmaticians consider this the broad sense of sanctification. See Luther's Large Catechism, the Apostle's Creed, paragraph 53 and following
- The United Methodist Church: The Articles of Religion of the Methodist Church - Of Sanctification
- "Distinctive Wesleyan Emphases (Page 2)". Archives.umc.org. 2006-11-06. Retrieved 2012-08-04.
- Catholic Encyclopedia: Sanctity
- Church of God in Christ. "What we believe". Retrieved Februar 9. 2011.
- Apostolic Faith Church. "Our Faith - Doctrines". Retrieved May 24. 2011.
- Mike Sullivan. "Five Views on Sanctification: An In-Depth Analysis".
- Christian Reformed Church. "The Belgic Confession".
- Assemblies of God USA. "Sanctification & Holiness".
- J. Robertson McQuilkin, "The Keswick Perspective," In Five Views on Sanctification (Grand Rapids: Academic Books, 1987), p. 156.
- Charles G. Trumbull, Victory in Christ (Fort Washington: Christian Literature Crusade, 1959), 84, 48.
- Brunstad Christian Church. "Our Faith".
- "The Doctrine and Covenants: Section 20". The Church of Jesus Christ of Latter-day Saints. Intellectual Reserve, Inc. Retrieved 28 October 2012.
- "Helaman 3:35". The Church of Jesus Christ of Latter-day Saints. Intellectual Reserve, Inc. Retrieved 28 October 2012.
- Oaks, Dallin H. (November 2000), "The Challenge to Become", Ensign: 32