1. Jesus, who became the priest with an oath by God (Heb 7:20-22)
    Ps 110:4, Heb 7:17

By oath, God confirmed Jesus as the priest in Christ’s ministry. (Heb 7:20-22, Ps 110:4, Heb 7:17)

Heb 7:20 And inasmuch as not without an oath he was made priest:
21 (For those priests were made without an oath; but this with an oath by him that said unto him, The Lord sware and will not repent, Thou art a priest for ever after the order of Melchisedec:)
22 By so much was Jesus made a surety of a better testament.

Ps 110:4 The Lord hath sworn, and will not repent, Thou art a priest for ever after the order of Melchizedek.

Heb 7:17 For he testifieth, Thou art a priest for ever after the order of Melchisedec.