Sforno on Numbers 25:12/ספורנו על במדבר כ״ה:י״ב

1את בריתי שלום. Peace with the angel of death. We have a similar meaning of this word שלום in Job 25,20 עושה שלום במרומיו, “He makes peace in His lofty regions.” [I assume that the reference is to the fact that the angel of death has no authority in the celestial regions. Ed.] Losses occur only as a result of confrontations by opposites. We find that as a result of this שלום, “peace, or armistice” with the angel of death Pinchas enjoyed an exceedingly long life on earth, more so than any other member of his generation. In fact, he was still serving as priest in the Tabernacle at Shiloh during the civil war between Binyamin and the other tribes. This occurred many years after the death of Joshua and the elders who were Joshua’s assistants. (Judges 20,28) Joshua 24,26 reports these elders as surviving Joshua for many years. If, as is indicated by the Talmud, Pinchas was still alive in the days of Yiphtach (Judges 11,26) he must have been 300 years old by that time. (compare either Bereshit Rabbah 60,3 or Pirke de Rabbi Eliezer chapter 47 on the subject of Pinchas)