For by a single offering, He has perfected for all time those who are being sanctified.”
Hebrews 10:14 ESV
Sanctification is defined in Discovery Bible Helps Word Study as ~
Cognate: 37 hagiázō (from 40/hágios, "holy") – to regard as special (sacred), i.e. as holy ("set apart"); sanctify. See 40 (hágios).
[37 (hagiazō) means "to make holy, consecrate, sanctify; to dedicate, separate" (Abbott-Smith).]
37/hagiazō ("sanctify") is to render or regard as holy, because something has been made different. This preeminently refers to the Lord transforming believers so they are unlike sin and like Himself.
Our Scripture today shows the process of Sanctification. Again, we see the tension in the phrase ‘perfected for all time’ and ‘those who are being’. ‘Perfected’ speaks to what His single offering accomplished, and ‘are being’ speaks to the ‘now' process, worked out in our daily lives through the activity of the Holy Spirit.
1 Corinthians 6:11 "And such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus and by the Spirit of our God."
2 Thessalonians 2:13 "But we ought always to give thanks to God for you, brothers beloved by the Lord, because God chose you as the firstfruits to be saved, through sanctification by the Spirit and belief in the truth.”
While we are admonished to be holy, sanctification is best understood as being "set apart because we have been made different. Our English Word ‘holy’ is defined as something, someone, dedicated or consecrated to God or a religious purpose; sacred. You can see it emphasizing being set apart rather than merely clean. Clean is the result, not the process.
The Helps Word Study further defines hagiazo ~
God sanctifies ("makes holy, 37/hagiázō) us through faith (4102/pístis, "His inworked persuasion"). Accordingly, faith (4102/pístis) and 37 (hagiázō) are directly connected.
Ac 26:18: "To open their eyes so that they may turn from darkness to light and from the dominion of Satan to God, that they may receive forgiveness of sins and an inheritance among those who have been sanctified (37/hagiázō, Gk perfect tense) by faith (4102/pístis) in (1519/eis) Me" (NASB).
In viewing sanctification as separation, we learn from Col. 1:13 that we have been (at the moment of acknowledging Romans 10:9-10) separated from the Kingdom of darkness and separated to the Kingdom of Light. This marks the beginning of the sanctification and the ongoing daily application of ‘those who are being sanctified’
2 Tim 2:21,22: ~ 21Therefore, if anyone cleanses himself from these things, he will be a vessel for honor, sanctified (37/hagiázō), useful to the Master, prepared for every good work. 22 Now flee from youthful lusts and pursue righteousness, love and peace, with those who call on the Lord from a pure heart" (NASB).
From God’s perspective, the believer has been sanctified in Christ. Outside of Christ we are a tainted vessel, requiring sanctification. Holiness recognizes something that has been dedicated to God. This is why the Apostle Paul wrote ~
Romans 6:19 "I am speaking in human terms, because of your natural limitations. For just as you once presented your members as slaves to impurity and to lawlessness leading to more lawlessness, so now present your members as slaves to righteousness leading to sanctification.”
Romans 12:1 to “present your body to God as a living sacrifice, holy and acceptable. This is your spiritual worship”.
1 Thess 4:3, 7 ~ "For this is the will of God, your sanctification… For God has not called us for the purpose of impurity, but in sanctification”.
Without believing that these biblical truths apply to our growth and development as believers, we cannot succeed in conforming to Christ. The Father has fulfilled his purpose and desire through Jesus’ obedience for every individual who will receive the work that He has done.
It is in the believing, receiving, and obeying that we find the greatest fulfillment as Christians. If our bodies are to be separated for God's purpose, they should not be used for things that defile them. A sanctified vessel is a pure vessel.
In John 17:17-19, Jesus prays for his disciples to be sanctified in truth and declares his sanctification so that we too might be sanctified. He was separated from and separated to, and we see his life displayed in the fruit of that separation.
"But now that you have been set free from sin and have become slaves of God, the fruit you get leads to sanctification and its end, eternal life." Romans 6:22