The connection between sanctification and holiness is clearer in the original languages of the Bible than in the English of today. In Hebrew and Greek, the two words share the same root. To sanctify means to declare, acknowledge as, or make holy.

In the Old Testament

To Israelites of Old Testament times, the basic meaning of holiness was not a condition of moral purity, but a state of being different or separate from the common things of life. God was holy (Exodus 15:11-12), and so were people and things set apart for him (Exodus 19:6; Exodus 29:29; Exodus 29:31; Exodus 30:25; Leviticus 27:30; Leviticus 27:33; Numbers 5:17). To sanctify a person or thing meant to separate it from the common affairs of life and consecrate it wholly to God (Exodus 13:2; Exodus 19:10; Exodus 19:23; Exodus 29:37; Exodus 29:44; Leviticus 27:21).

Since sanctification meant separation from common use for God’s use, sanctification soon included in it those ideas of moral purity that we today more commonly associate with the word. Both Old and New Testament writers emphasized that formal sanctification was of value only when it was accompanied by practical sanctification (2 Chronicles 29:15-16; 2 Chronicles 29:34; 2 Chronicles 30:15; 2 Chronicles 30:17; Romans 6:19; Romans 6:22). (For a fuller discussion on the biblical ideas of holiness see HOLINESS.)

In the New Testament

The New Testament speaks about the relationship aspect of sanctification (setting a person or thing apart for God) and the moral aspect (living an upright life). Jesus Christ was sanctified in both aspects. He was wholly consecrated to God (John 17:19; Acts 3:14) and he was morally perfect in his life (Hebrews 7:26; 1 Peter 2:22).

Although their experience differs from Christ’s, Christians also may be spoken of as sanctified in the two senses we have been considering. In both cases Christ is the means of their sanctification.

Firstly, through Christ’s death believers are brought into a right relationship with God (1 Corinthians 1:30; Hebrews 10:10). God is the one who sanctifies them, as he cleanses them of their sin and declares them holy and righteous in his sight (2 Thessalonians 2:13; Hebrews 2:12; Hebrews 10:14-17; 1 Peter 1:2). In this sense, sanctification is another way of looking at the truth that is expressed in justification (1 Corinthians 6:11; see JUSTIFICATION). Believers are ‘saints’, meaning ‘the sanctified ones’. They are ‘God’s holy people’ (Romans 1:7; 1 Corinthians 1:2; Ephesians 1:1).

Secondly, sanctification means that Christians are to have a moral and spiritual change in their lives. God has declared them holy (because of what Christ has done on their behalf) and they must now make that true in practice. They are sanctified; now they must be sanctified (Romans 6:8-11; Romans 6:19-22; 1 Thessalonians 4:3; 1 Thessalonians 5:23; Hebrews 12:14). This will involve a battle with the old sinful nature (the flesh), but through the power of the living Christ within, they can have victory over the flesh and be progressively changed into the likeness of Christ (Romans 8:9-12; Romans 12:1-2; Colossians 3:9-10; Colossians 3:12; 1 Peter 1:14-15).

There are two other uses of the word ‘sanctify’ that should be noted. In the first, people are said to sanctify God when they acknowledge his holiness and reverence him as Lord (Numbers 20:12; Isaiah 8:13; Isaiah 29:23; 1 Peter 3:15). In the second, God is said to sanctify the unbelieving husband whose wife has become a Christian. This does not mean that God makes the man into a Christian, but that he accepts the man as part of an equal marriage. God considers the marriage to be holy on account of the believing partner; it is a lawful union (1 Corinthians 7:14).

Bibliography Information
Fleming, Don. Entry for 'Sanctification'. Bridgeway Bible Dictionary. https://www.studylight.org/dictionaries/eng/bbd/s/sanctification.html. 2004.

Bible Dictionaries Sanctification

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Sanctification