In Scripture, sanctification involves separation and purification for God’s purposes. The Scriptures also declare how God wills for the sanctification of those who believe in Jesus (1 Thessalonians 4:3). Yet how and when are believers sanctified, and who is involved in sanctification? People have been disputing such questions for hundreds of years. What does Scripture say?
On the surface, the Scriptures might seem to present contradictory information. In some passages, the sanctification of the believer is spoken of as if it has already been accomplished (e.g. Romans 15:16, 1 Corinthians 1:2, 6:11, 2 Thessalonians 2:13, Hebrews 10:10, 10:29); in other passages, the sanctification of the believer is spoken of as if it is still being continually realized (e.g. Romans 6:19, 22, 1 Thessalonians 4:3-4, 7, 1 Timothy 2:15, Hebrews 12:14). In many passages, sanctification is spoken of as having been accomplished by God through Jesus (Hebrews 10:10), but also through the Holy Spirit (1 Corinthians 6:11, 2 Thessalonians 2:13, 1 Peter 1:2); in other passages, sanctification is something for which the believer must strive (Romans 6:19, 1 Thessalonians 4:3-4, 1 Timothy 2:15, Hebrews 12:14). How are we to make sense of the sanctification of the believer?
We do well to consider the more physical type of sanctification described in the Old Testament. In the wilderness, God commanded Moses and the Israelites to consecrate Aaron and his sons to serve as priests before God (Exodus 28:1-29:37); this was accomplished in Leviticus 8:1-9:24. On account of this consecration, Aaron and his sons were separated out from the rest of Israel and made pure through the sacrifices offered. Nevertheless, when Aaron and his sons would present themselves before God on the Day of Atonement to make atonement for the sins of the people, they would have to first offer sacrifices for their own sin; they needed to be cleansed before they could offer sin offerings for the cleansing of the people (Leviticus 16:1-6, Hebrews 7:27-28, 9:6-7, 24-26).
Even though we understand that such sacrifices could not truly make perfect the one providing them, since only the blood of Jesus, fully holy and righteous, can accomplish that (Hebrews 9:6-15), we can still learn about the nature of sanctification from this example. Before they could effectively minister before God, Aaron and his sons first had to be separated out for God’s purposes and made pure. Likewise, before believers in Christ can effectively minister before God, they must first be separated out for God’s purposes and made pure; this is accomplished when the believer comes to belief in God in Christ, confesses Jesus, repents of sin, and receives the cleansing from sin that comes from being immersed in water in the name of Jesus (Acts 2:38, Romans 10:9-10, 1 Corinthians 6:11, Titus 3:4-5, Hebrews 9:14). But just as Aaron and his sons still needed to provide sacrifices for their own sin after their consecration, since they had sinned and needed cleansing again, so it is with believers in Christ: we still fall short of God’s glory and struggle with sin, and so we continually need to be purified from sin (Romans 3:23, 1 John 1:8-9).
It was God who commanded Moses and the Israelites to consecrate Aaron and his sons; it was God who commanded the sacrifices for sin; it was God who ultimately would consider such deeds and sacrifices to be acceptable and efficacious before Him. And yet Moses and Aaron and his sons needed to actually accomplish all the things which God commanded; Aaron and his sons were to work to avoid defilement and impurity and to offer the requisite sacrifices. Likewise, in the new covenant, God has provided the ultimate means by which the believer can receive cleansing from sin, the blood of God’s Son Jesus (Hebrews 10:10). We are unable to cleanse ourselves from the stain of our sins; since we have all sinned, we stand condemned by law (Romans 3:20, James 2:10-11). Since we are unable to cleanse ourselves, Jesus is the One who purifies the believer from sin through the cleansing from His blood which comes by the cleansing in the water of baptism (cf. Ephesians 5:25-27, Hebrews 9:11-15). But it is for the believer to put his or her trust in God in Christ and do the things which He has commanded so as to receive that cleansing (Romans 6:19, 22). Believers are also expected to align their will toward righteousness and purity, manifesting the fruit of the Spirit: love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, and self-control (Galatians 5:22-23). Nevertheless, all such efforts are futile if they are not empowered by God through the Holy Spirit and considered efficacious for their purposes by Him (Ephesians 3:16, 2 Thessalonians 2:13, 1 Peter 1:2).
It is rightly said that God’s will for us is our sanctification, that we may be separated out for God’s purposes and pure before Him (1 Thessalonians 4:3). We are sanctified when we turn back to God and are reconciled to Him, yet we stand in constant need for cleansing because of our deficiencies. We are to strive toward righteousness, holiness, and purity, but we cannot fully accomplish such on our own, and therefore must entrust ourselves to God who is able to empower us toward purity and holiness if we seek to align our will to His. Let us obtain and maintain sanctification and be conformed to the image of God in Christ!