The grandson of Aaron and son of Eleazar, the High Priests (Exodus 6:25), he distinguished himself as a youth at Shittim with his zeal against the heresy of Peor.

This Egyptian root (nḥsj, with the preformative pʾ as a definite article) appears in Exodus 6.25 as the personal name of Aaron's grandson, Phinehas (= Pa-neḥas)".

[11] Revelation describes Jesus as speaking to one of seven Christian churches: "Nevertheless, I have a few things against you: You have people there who hold to the teaching of Balaam, who taught Balak to entice the Israelites to sin by eating food sacrificed to idols and by committing sexual immorality."

Giving a more elaborated version of events, the 1st-century Romano-Jewish historian Flavius Josephus asserts that Balaam sent for Balak and the princes of Midian and told them that, if they wished to bring evil upon Israel, they would have to make the Israelites sin.

Among those slain in the expedition were five Midianite kings, Evi, Rekem, Zur, Hur, and Reba, and also Balaam, son of Beor.

When the tribes of Reuben and Gad, together with the half-tribe of Manasseh, depart to take possession of their lands beyond the Jordan, they build a great altar on the other side; the remainder of the Israelites mistake this for a separatist move to set up a new religious centre, and send Phinehas to investigate.

According to some rabbinical commentators, Phineas sinned due to his not availing his servitude of Torah instruction to the masses at the time leading up to the Battle of Gibeah.

[20][21] Pinechas is the name of the 41st weekly Parashah or portion in the annual Jewish cycle of Torah reading and the eighth in the book of Numbers.

It derives from the Babylonian Talmud (Sotah, Ch.22, p. 2), where it is attributed to the Hasmonean King Alexander Jannaeus (see Hebrew Wikipedia עושה מעשה זמרי ומבקש שכר כפנחס‎).