Significance of "Holy to the Lord" Inscription on High Priest's Forehead

Sources

1. Torrey's Topical Textbook “Torrey's Topical Textbook: High Priest, The — Specially called of God -- Ex 28:1,2; Heb 5:4. Consecrated to his office -- Ex 40:13; Le 8:12. Was called The priest. -- Ex 29:30; Ne 7:65. God's high priest. -- Ac 23:4. Ruler of the people. -- Ex 22:28; Ac 23:5. The office of, hereditary -- Ex 29:29. Next in rank to the king -- La 2:6. Often exercised chief civil power -- 1Sa 4:18. Duties of Offering gifts and sacrifices. -- Heb 5:1. Lighting the sacred lamps. -- Ex 30:8; Nu 8:3. Making atonement in the most holy place once a year. -- Le 16:1-34; Heb 9:7. Bearing before the Lord the names of Isra”
2. Easton's Bible Dictionary “Easton's Bible Dictionary: High priest — Aaron was the first who was solemnly set apart to this office (Ex. 29:7; 30:23; Lev. 8:12). He wore a peculiar dress, which on his death passed to his successor in office (Ex. 29:29, 30). Besides those garments which he wore in common with all priests, there were four that were peculiar to himself as high priest: (1.) The "robe" of the ephod, all of blue, of "woven work," worn immediately under the ephod. It was without seam or sleeves. The hem or skirt was ornamented with pomegranates and golden bells, seventy-two of each in alternate order. The soundi”
3. Torrey's Topical Textbook “Torrey's Topical Textbook: Ephod, The — The emblem of the priestly office -- Ho 3:4. Worn by The high priest. -- 1Sa 2:28; 14:3. Ordinary priests. -- 1Sa 22:18. Persons engaged in the service of God. -- 1Sa 2:18; 2Sa 6:14. Generally of linen. -- 1Sa 2:18; 2Sa 6:14. For the high priest Commanded to be made. -- Ex 28:4. Made of offerings of the people. -- Ex 25:4,7. Made of gold, blue, purple, scarlet, &c. -- Ex 28:6; 29:2,3. Shoulders of, joined by onyx stones engraved with names of the twelve tribes of Israel. -- Ex 28:7,9-12; 39:4,6,7. Had a girdle of curious work. -- Ex 28:8. Breastplate of ”
4. Leviticus (Baptist/Reformed) “John Gill on Leviticus 8:9: And he put the mitre upon his head,.... Which was made of fine linen, and was a wrap of that of a considerable length about his head, Exo 28:39. also upon the mitre, even upon his forefront, did he put the golden plate; which was put upon the forehead of the high priest, reaching from ear to ear, and was fastened to the mitre with a blue lace, and had on it this inscription, "holiness to the Lord": Exo 28:36 and is here therefore called the holy crown: denoting both the sanctity and the dignity of the high priest, and typical of Christ, who is holiness itself, a”
5. Leviticus (Protestant academic) “Tyndale House on Leviticus 8:9: 8:9 The turban worn by the high priest was made of linen and was distinct from the headdresses of the common priests (Exod 28:40). The gold medallion was suspended from the turban and bore an inscription that read, “Holy to the Lord” (Exod 28:36). With the names of the tribes on his shoulders and over his heart and the dedication to the Lord on his forehead, the high priest was clearly marked as the people’s representative to God and God’s representative to the people. In this mediating role, the high priest modeled the standard for all priests.”
6. Exodus (Baptist/Reformed) “John Gill on Exodus 28:35: And thou shalt make a plate of pure gold,.... It was, as Jarchi says, two fingers broad, and reached from ear to ear, and so Maimonides (f); it is sometimes called the holy crown, and the plate of the holy crown, Exo 29:6, this was a priestly crown, for priests were very honourable and dignified persons, especially the high priest among the Jews; and even among the Gentiles it was common for their kings to be priests: and though this crown may denote the kingly power of Christ, yet as residing in him who is a priest, for he is a priest on his throne, Zac 6:13, and so”
7. Zechariah (Protestant academic) “Tyndale House on Zechariah 3:5: 3:5 The high priest’s turban bore a gold medallion inscribed with the words “Holy to the Lord” (Exod 28:36-38; see also study note on Zech 14:20). The clean turban was placed on Jeshua’s head as an act of ordination that reinstated him as priest and mediator for the people.”
8. Exodus (Baptist/Reformed) “John Gill on Exodus 28:37: And it shall be upon Aaron's forehead,.... That is, the plate of gold, with the inscription on it, holiness to the Lord, and so was very visible and legible. The Targum of Jonathan adds, from temple to temple, that is, from the furthermost end of the one, to the furthermost end of the other, the same as from ear to ear; see Gill on Exo 28:36 the use of it follows: that Aaron may bear the iniquity of the holy things, which the children of Israel shall hallow in all their holy gifts; this supposes that the sacrifices of the children of Israel, which they brought to t”
9. Exodus (Baptist/Reformed) “John Gill on Exodus 29:6: And thou shall put the mitre upon his head,.... Which was made of linen, and was a wrap of linen about his head in the form of a turban: and put the holy crown upon the mitre; the holy crown was a plate of gold which had these words, "holiness to the Lord", engraven on it; and so says the Targum of Jonathan,"on which the holy name was engraven;''the mitre was upon the top of his head, this in the forefront of that; it was upon Aaron's forehead, and reached from ear to ear, and was fastened behind with a blue lace; this was like a crown or a diadem, and denotes the h”