We are not sanctified when we are justified.
"we have been sanctified through the offering of the body of Jesus Christ once for all." (Heb 10:10)
We are still just as dirty as we were prior to regeneration.
"But you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus and by the Spirit of our God." (1 Co 6:11)
The only thing that happens during justification is that Christ (who already paid for our sins) stands between us and the Father absorbing the wrath of His anger, which then absolves us from having to pay for our sins, ourselves.
"Therefore, if anyone is in Christ, he is a new creation; old things have passed away; behold, all things have become new." (2 Co 5:17)
And there is no such thing as self-sanctification. It is the Holy Spirit’s work in us that makes it possible for us to be conformed to the image of Christ.
OT
Josh 3:5 And Joshua said to the people, “
Sanctify yourselves, for tomorrow the Lord will do wonders among you.”
Josh 7:13 Get up, sanctify the people, and say, ‘
Sanctify yourselves for tomorrow, because thus says the Lord God of Israel: “There is an accursed thing in your midst, O Israel; you cannot stand before your enemies until you take away the accursed thing from among you.”
1 Sam 16:5 And he said, “Peaceably; I have come to sacrifice to the Lord.
Sanctify yourselves, and come with me to the sacrifice.” Then he consecrated Jesse and his sons, and invited them to the sacrifice.
1 Chron 15:12 He said to them, “You are the heads of the fathers’ houses of the Levites;
sanctify yourselves, you and your brethren, that you may bring up the ark of the Lord God of Israel to the place I have prepared for it.
2 Chron 29:5 and said to them: “Hear me, Levites! Now
sanctify yourselves, sanctify the house of the Lord God of your fathers, and carry out the rubbish from the holy place.
NT
2 Cor 7:1 Therefore, having these promises, beloved, let us
cleanse ourselves from all filthiness of the flesh and spirit, perfecting holiness in the fear of God.
Eph 4:22 that you
put off, concerning your former conduct,
the old man which grows corrupt according to the deceitful lusts,
Eph 4:24 and that you
put on the new man which was created according to God, in true righteousness and holiness.
2 Tim 2:21 Therefore if anyone
cleanses himself from the latter, he will be a vessel for honor, sanctified and useful for the Master, prepared for every good work.
1 Pet 3:15 But
sanctify the Lord God in your hearts, and always be ready to give a defense to everyone who asks you a reason for the hope that is in you, with meekness and fear;