1Thessalonians 4:1-7 Furthermore then we beseech you, brethren, and exhort you by the Lord Jesus, that as you have received of us how you ought to walk and to please God, so you would abound more and more. For you know what commandments we gave you by the Lord Jesus. For this is the will of God, even your sanctification, that you should abstain from fornication: That every one of you should know how to possess his vessel in sanctification and honour; Not in the lust of concupiscence, even as the Gentiles which know not God: That no man go beyond and defraud his brother in any matter: because that the Lord is the avenger of all such, as we also have forewarned you and testified. For God had not called us unto uncleanness, but unto holiness.
If sin is not involved in the person or thing set apart, then no sin is cleansed in the process of setting apart (continues):  The same people were sanctified many times so sanctification cannot be limited to one act (Ex. 19:14, 22; 28:41; 29:33, 44; 30:29; Lev. 8:30).  People have sanctified themselves (Lev. 11:44; 20:7). Did they take an old man out of themselves?  The same people that sanctified themselves (Lev. 11:44; 20:7) were also sanctified by Moses (Ex. 19:10-14) and by God (Ex. 29:43-44; 31:13; Lev. 20:8; 21:8, 15, 23; 22:9, 16). Which ones took the old man out?  All the firstborns of Israel were sanctified at birth (Ex. 13:2; Num. 8:17). If the old man was taken out at this time, then none of them had an old man after that.  Sanctified disciples (John 13:10; 15:3) were further sanctified in the same sense that the sanctified Christ (John 10:36) further sanctified Himself (John 17:17-19).  The seventh day was sanctified without sin and cleaning being involved (Gen. 2:3-4).
However, if sin and filth are involved in a person or a material thing to be set apart unto God, then such must be dealt with to make it presentable to God.
To be continued…