'Rashi': This is read with "Hashem Imo." Earlier, he prophesized. Because he did not permitted Yiftach's vow, the Shechinah departed from him (Koheles Rabah 10:17). Radak #2 - he was able to protest against Zimri, for then, Hashem Imo. He could not protest at the time of Pilegesh b'Giv'ah (after Yiftach), for then Hashem was not with him.

Radak #1: This is read with "Nagid Hayah Aleihem." Earlier, Pinchas was appointed over them, just like his father Elazar. This is because "Hashem Imo" - he was greater than Bnei Itamar.

Radak: Some say that the earlier Pinchas ben Elazar was a Kohen, and Hashem Imo (he had Ru'ach ha'Kodesh). This Pinchas was a Levi without Ru'ach ha'Kodesh, but he was a Gadol, and a leader over the Leviyim ¹ .

Malbim: When Bnei Yisrael entered Eretz Yisrael, Pinchas was the head ² . Hashem was Imo - "Hineni Nosen Lo Es Brisi Shalom."