Matthew Poole and continuators on Numbers 25:12

12 Wherefore say, Behold, I give unto him my covenant of peace .

(i. e.) The covenant of an everlasting priesthood, as it is expounded v. 13. which is called a covenant of peace, partly with respect to the happy effect of this heroical action of his whereby he made peace between God and his people, and partly with regard to the principal end and use of the Priestly office, which was constantly to do that which Phinehas now did, even to mediate between God and Men, to obtain and preserve his own and Israels peace and reconciliation with God by offering up sacrifices and incense and prayers to God on their behalf, Numb. 16. 47, 48. as also by turning them away from iniquity, which is the onely peace-breaker, and by teaching and pressing the observation of that Law, which is the onely bond of their peace, Mal. 2. 5, 6, 7.