1. Christ, who is a merciful and faithful High Priest in things pertaining to God, to make propitiation for the sins of the people (Heb 2:17)
    1 Sam 2:35, Rom 8:3, Rom 3:25, Heb 3:1, Heb 4:14, Heb 5:5-10, Heb 7:28, Heb 8:1, Heb 9:11-12, 1 Jn 2:1-2

Christ means the anointed one. In the Old Testament, kings, priests, and prophets were anointed.

In the Old Testament, it was foretold that God would raise up a faithful priest and establish him as an eternal priest. (1 Sam 2:35)

1 Sam 2:35 And I will raise me up a faithful priest, that shall do according to that which is in mine heart and in my mind: and I will build him a sure house; and he shall walk before mine anointed for ever.

God made Jesus, the Son of God, bear our sins. And God made Jesus the propitiation sacrifice. (Rom 8:3, Rom 3:25)

Rom 8:3 For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh:

Rom 3:25 Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;

Jesus became the high priest and sacrificed himself so that he died to save us. (Heb 2:17, Heb 3:1, Heb 4:14, Heb 5:5-10, Heb 7:28)

Heb 2:17 Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.

Heb 3:1 Wherefore, holy brethren, partakers of the heavenly calling, consider the Apostle and High Priest of our profession, Christ Jesus;

Heb 4:14 Seeing then that we have a great high priest, that is passed into the heavens, Jesus the Son of God, let us hold fast our profession.

Heb 5:5 So also Christ glorified not himself to be made an high priest; but he that said unto him, Thou art my Son, to day have I begotten thee.
6 As he saith also in another place, Thou art a priest for ever after the order of Melchisedec.
7 Who in the days of his flesh, when he had offered up prayers and supplications with strong crying and tears unto him that was able to save him from death, and was heard in that he feared;
8 Though he were a Son, yet learned he obedience by the things which he suffered;
9 And being made perfect, he became the author of eternal salvation unto all them that obey him;
10 Called of God an high priest after the order of Melchisedec.

Heb 7:28 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.