John Wesley on Numbers 25:13

At everlasting priesthood - To continue as long as the law and common - wealth of the Jews did. But this promise was conditional, and therefore might be made void, by the miscarriages of Phinehas's sons, as it seems it was, and thereupon a like promise was made to Eli of the line of Ithamar, that he and his should walk before the Lord, namely, in the office of high - priest, for ever, which also for his and their sins was made void, 1Sam 2:30. And the the priesthood returned to Phinehas's line in the time of Solomon, 1Kings 2:26,27,34.