Guaranteed not to have too many comments today, as I'm going back to more standard Torah dicsussion : ) Maybe more some other time - I would just encourage anyone interested to follow my snippits of quotes to the sources themselves. Reminder: please learn and daven as a zechus for Eretz Yisrael.
Hashem instructs Moshe to SAY regarding Pinchas "Hininei nosein lo es brisi shalom", I am giving him my covenant or peace. Why does this have to be a public proclamation and not private news? Perhaps it was because of the rumbelings of disapproval that questioned how Pinchas could kill a leader of a sheivet, but perhaps there is something more. The Rambam writes in in into to Peirush haMishna that what Hashem privately promises a Navi is subject to not coming to fulfillment. We find that although Hashem promised to protect Ya'akov, he was nonetheless worried over encountering Eisav because he thought his sins would negate the promise. Yet, the Rambam writes with respect to nevuah, words that the prophet is instructed to deliver to the people, there is a gurantee that what is said will be unconditionally fulfilled (see Rambam Yesodei HaTorah ch 10 that a Navi can be tested by whether his words are fulfilled). The Meshech Chochma writes that Hashem asked Moshe to SAY that Pinchas receives the bris of shalom so that this promise would be unconditionally guaranteed for eternity and not subject to the personal zechuyos of Pinchas.
The Meshech Chocham cites this idea in many places, e.g. Why is it that Avraham laughs when told that he will have a son and nothing comes of it, but Sarah is chastised? M.C. distinguishes between the promise told to Avraham in private which depends on her merit for fulfillment, and the nevuah spoken to Sarah which was a guarantee.
What the Meshech Chochama does not tell you is that the MaHaRaL strongly disagrees with this Rambam - see ch 7 of Gevuros Hashem. The MaHaRaL argues that any nevuah by definition is guaranteed to occur. So why then was Ya'akov afraid? MaHaRaL writes that there is a difference between nevuah and a havtacha. The former reveals something fundemental about the nature of the beriya which is not subject to change. The latter is based on the personal relationship between the tzadik, prophet, or people and Hashem. If I had to offer an analogy: nevuah would be like predicting that my 5 year old daughter would grow from 4 feet to 5 feet as she gets older. A havtacha would be like promising to buy my 4 year old daugher an ice cream because she is a good girl - even if unstated, it is understood that if she misbehaves, all bets are off. The MaHaRaL develops a number of key concepts in that chapter - yosef chacham v'yikach lekach.