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.
Hebrews 8:1 Now of the things which we have spoken this is the sum: We have such an high priest, who is set on the right hand of the throne of the Majesty in the heavens;
Hebrews 9:11 But Christ being come an high priest of good things to come, by a greater and more perfect tabernacle, not made with hands, that is to say, not of this building; 12 Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us.
1 John 2:1 My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous: 2 And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world.