We do not see this question explicitly asked in Scripture, and yet the necessity of sanctification is repeatedly emphasized. Paul clearly says: “For this is the will of God, your sanctification” (1 Thessalonians 4:3). Therefore, each Christian should ask themselves the question: “Lord, what do I need to do in order to be sanctified?” Although it is God alone who can sanctify, we need to fulfill the conditions required. When we were saved, there were prerequisites present for God to do this work in our soul. Similarly, to be sanctified wholly, we need to take to heart the words in Romans 12:1, “I beseech you therefore, brethren, by the mercies of God, that you present your bodies a living sacrifice, holy, acceptable to God, which is your reasonable service.”
It is necessary to be sanctified completely in order to be better equipped for service in the Kingdom of God. Since we serve God and others by using the members of our body, sanctification is both for soul and body. Only if we are totally consecrated to God are we able to offer an acceptable and reasonable service to our Lord.
Romans 12:1 is an urgent plea or appeal addressed to believers. It cannot refer to those who “are dead in trespasses and sins” (Ephesians 2:1) but only to those who “have passed from death to life” (1 John 3:14), since the sacrifice must be “a living sacrifice” which is “holy.” This consecration, this sacrifice, includes dying – dying to my ego, my selfish agenda. My life now belongs to God. This is wonderfully expressed by the Apostle Paul when he says: “I have been crucified with Christ; it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by the faith in the Son of God, who loved me and gave Himself for me” (Galatians 2:20).
In order for God to sanctify us fully, we must be willing to give up our own agenda. It is no longer our plans, our thoughts, our wants which we seek but God’s Kingdom. We subject our will and everything we do to His leading.
We are sanctified by the truth
Jesus prayed to the Father and said: “Sanctify them by Your truth. Your word is truth” (John 17:17). It is only in harmony with the truth of God’s Word that we can attain this state of grace. We must have unconditional faith in the Word of God because “it is the power of God to salvation for everyone who believes” (Romans 1:16) and also “because God from the beginning chose you for salvation through sanctification by the Spirit and belief in the truth” (2 Thessalonians 2:13). Therefore, we must obey the truth.
Obeying the truth to be sanctified completely includes what Paul outlines in 1 Thessalonians 5:15-23, “See that no one renders evil for evil to anyone, but always pursue what is good both for yourselves and for all. Rejoice always, pray without ceasing, in everything give thanks; for this is the will of God in Christ Jesus for you. Do not quench the Spirit. Do not despise prophecies. Test all things; hold fast what is good. Abstain from every form of evil. Now may the God of peace Himself sanctify you completely; and may your whole spirit, soul, and body be preserved blameless at the coming of our Lord Jesus Christ.”
The promise that Jesus gave His disciples – to ask the Father to send them the Holy Spirit – rests on the condition that they keep His commandments (John 14:15-18). Peter, too, verifies that God gives the Holy Spirit to those who obey Him (Acts 5:32).
We need to seek, in all sincerity, to be sanctified completely.
“Ask and it will be given to you; seek, and you will find; knock, and it will be opened to you. For everyone who asks receives, and he who seeks finds, and to him who knocks it will be opened. If a son asks for bread from any father among you, will he give him a stone? . . . If you then, being evil, know how to give good gifts to your children, how much more will your heavenly Father give the Holy Spirit to those who ask Him” (Luke 11:9-13). When the disciples were staying in Jerusalem (since Jesus told them to do so until they were filled with the Holy Spirit), we read that they “continued with one accord in prayer and supplication” (Acts 1:14). This shows us that when Jesus has promised us something, this does not relieve us from the duty to earnestly pray to God for it. It has been repeatedly experienced that when we pray earnestly, then we will receive.
We must exercise faith
When we consecrate our lives completely to God for His service and offer ourselves to Him fully as a living sacrifice, then we have done our part. If we fulfill the Lord’s will in this way and believe His promise, then He sanctifies us through the blood of His Son. Through faith we can claim our promised “inheritance among those who are sanctified by faith” (Acts 26:18).