John Wesley on Numbers 25:12

My covenant of peace - That is, the covenant of an everlasting priesthood, as it is expounded, Nu 25:13, 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 of the priestly office, which was constantly to do that which Phinehas now did, even to meditate between God and men, to obtain and preserve his own and Israel's peace and reconciliation with God, by offering up sacrifices and incense, and prayers, to God on their behalf, as also by turning them away from iniquity, which is the only peace - breaker, and by teaching and pressing the observation of that law, which is the only bond of their peace.