Exodus 39:30-32 (KJV)

30 And they made the plate of the holy crown of pure gold, and wrote upon it a writing, like to the engravings of a signet, HOLINESS TO THE LORD.

31 And they tied unto it a lace of blue, to fasten it on high upon the mitre; as the LORD commanded Moses.

32 Thus was all the work of the tabernacle of the tent of the congregation finished: and the children of Israel did according to all that the LORD commanded Moses, so did they.

The last thing that was done for the work of the tabernacle was to engrave the signet with HOLINESS TO THE LORD and fasten it to the turban for the high priest. From the 
Believers Bible we see: 39:30, 31 The gold plate on the high priest’s turban was engraved like a signet with the words “HOLINESS TO THE LORD” so that he might bear the iniquity of the holy things (Exo 28:38). All that we do is stained with sin, but our worship and service are purged from all imperfection by our Great High Priest before they reach the Father. 
Finis Dake commented: The high priest was the atoning mediator between God and Israel, and consecrated the holy gifts that they might be accepted by the Lord (Exo 28:38, Exo 28:43). 

Hebrews 2:16-18 (ASV)

16 For verily not to angels doth he give help, but he giveth help to the seed of Abraham.

17 Wherefore it behooved him in all things to be made like unto his brethren, that he might become a merciful and faithful high priest in things pertaining to God, to make propitiation for the sins of the people.

18 For in that he himself hath suffered being tempted, he is able to succor them that are tempted.

Now Jesus Christ has become the faithful High Priest. He is the perfect High Priest.

Hebrews 7:23-28 (KJV)

23 And they truly were many priests, because they were not suffered to continue by reason of death:

24 But this man, because he continueth ever, hath an unchangeable priesthood.

25 Wherefore he is able also to save them to the uttermost that come unto God by him, seeing he ever liveth to make intercession for them.

26 For such an high priest became us, who is holy, harmless, undefiled, separate from sinners, and made higher than the heavens;

27 Who needeth not daily, as those high priests, to offer up sacrifice, first for his own sins, and then for the people’s: for this he did once, when he offered up himself.

28 For the law maketh men high priests which have infirmity; but the word of the oath, which was since the law, maketh the Son, who is consecrated for evermore.

In the book of Hebrews (NKJV) “High Priest” is mentioned 16 times explaining Jesus Christ priestly role. And because He is HOLY so we also should be HOLY:

1 Peter 1:13-16 (KJV)

13 Wherefore gird up the loins of your mind, be sober, and hope to the end for the grace that is to be brought unto you at the revelation of Jesus Christ;

14 As obedient children, not fashioning yourselves according to the former lusts in your ignorance:

15 But as he which hath called you is holy, so be ye holy in all manner of conversation;

16 Because it is written, Be ye holy; for I am holy.

As the High Priest, Jesus Christ enables us to also be HOLY in all our conduct. This is realised by us “bracing up our mind (renewing it by the Word of God) and taking courage in face of the trials that we are called to go through.” (Paraphrased from Finis Dake), having total trust in the grace of Jesus Christ, (given to us by Him through the revelation of the Gospel), resulting in us being obedient to His word bringing about our nonconformity to the lusts we walked in before.
Let us encourage each other as we gather together to be holy in all our conduct, displaying Christs our High Priest HOLINESS TO THE LORD.