Numbers 25:13
And he shall have it, and his seed after him, even the covenant of an everlasting priesthood; because he was zealous for his God, and made an atonement for the children of Israel. And he shall have it, and his seed after him, even the covenant of an everlasting priesthood; because he was zealous for his God, and made an atonement for the children of Israel.
This promise belongs to the account of Israel's apostasy at Baal-peor, when the people joined in heathen worship and the apostasy spread through the camp. Phinehas, the son of Eleazar, the son of Aaron the priest, rose with a javelin and executed the Israelite man and the Midianite woman in the tent while the congregation wept.
Because he was zealous for his God, his decisive act in executing judgment against public defiance made atonement for Israel. That zeal turned God's wrath away so Israel was not consumed in jealousy, and it stopped the plague after twenty-four thousand had died for joining Baal-peor.
In reward God gave him a covenant of peace, even an everlasting priesthood for him and his seed and descendants after him. The account shows the Lord makes a clear distinction between those who obey His commandments and those who disobey, in that those who followed Baal-peor were destroyed while those who cleaved to the Lord were kept alive, so obedience brings life.
The whole event stands as an example written for admonition upon those on whom the ends of the world are come. It warns him who thinks he stands to take heed lest he fall, with the assurance that temptation is common to man and God will make a way to escape.