Can Jews and Muslims Observe Rosh HaShanah Together?

Shana Tova [(have) a good year]! Today is Jewish and Muslim new year's day, a.k.a. Rosh HaShanah and 1 Muharram! It is a solemn month where, especially for the first ten days, revelry would be inappropriate.
For Jews, it is the head ("rosh") of the ("ha") year ("shanah"). This is etymologically related to "Ras as-Sanah," the alternative name of the Muslim New Year. In Islam, the "harram" is the sacred, so Mu-harram is a sacred month where wars are forbidden. This is ordained by Allah a month of peace, the second holiest month following Ramadan, in a tradition going back to pre-Islamic Arabia which Allah upholds in the Qur'an (9:36). Fighting can only happen in self-defense, and in reality, Muharram has seen the martyring of Husayn, Muhammad's grandson, Ali's son. But imagine a world where developed nations hold off on counter-insurgencies and instead focus on negotiations for four months out of the year?

Jews believe in a Messianic Age, the coming of the age of peace and the end of warfare. The Messiah restores Eden ("and it was good" peace-&-order of Eden in Genesis -> "the lion lays down with the lamb/ weapons are beaten into farm tools" Book of Isaiah on the 'End Times'). Jews believe that today encompasses the anniversary of G-d creating humanity- reaffirming G-d alone is king. War, and not just war but oppression, is a result of humans with a G-d-Complex (modern-day kings): omnipotent, omnipresent, and omniscient. Yasiin Bey (Mos Def) says

"You got a lot of societies and governments/ Tryin to be G-d, wishing that they were G-d / They wanna create satellites and cameras everywhere / And make you think they got the all-seeing eye" 

("Fear Not of Man" - best song!). Islam tries to make it a habit to counter these tendencies- "inshallah" (if G-d wills it) vs. omnipotence, and "Allahu Alim" (G-d knows best") vs. omniscience, are common sayings.

Alternative to the arrogant-human-king is the idea of the Tiller-Caliph. Genesis labels human as the upkeeper/servant/tiller of the soil (2:15 "serve it and keep it"), only having dominion insofar as naming things and obtaining a livelihood such as procuring food (cattle to till the soil, etc.) - which, by the way, is only vegetables. Meat-eaters in the food chain symbolize predatory impulses among people- thus in the End Times the "lion" (aggressive people) lays down with the "lamb" (gentle people). In Eden and in truth, humans work in the maintenance department, not administration.

In the Qur'an, the Queen of Sheba protests, "Indeed kings - when they enter a city, they ruin it." As we see in the Hebrew Bible, Joseph and Solomon become corrupted when they think with the "power-over" model of a king (recall- Joseph becomes a cunning businessman whom Pharaoh hands the government over to, like today's corporate-run government) as opposed to the "power-with" model of mutuality and reciprocity.

In one saying of Muhammad (pbuh), he distinguishes between the era of kingdoms - starting with the horrific attacks on the house of the fourth Caliph Imam 'Ali -and the era of the caliphate.

Allah's alternative to kings lording it over people in the Qur'an is that what applies to Eve and Adam applies to *everyone*. Addressing its readers- the Qur'an says, "And (G-d) is the one who made you khalāifa (on) the earth (6:165; 35:39)". Khalāifa/Caliph doesn't mean "king" -  but "successors/vice-regents/G-d's representatives on earth". The first caliph of Islam, Abu Bakr, embodied the "power-with" model when he said,

"I have been given authority over you, though I am not the best of you. If I do well, help me; and if I do wrong, set me right. The weak among you shall be strong in my eyes until I have secured his rights, inshAllah; and the strong among you shall be weak with me until I have wrested from him the rights of others, inshAllah. Obey me for so long as I obey G-d and his Messenger. But if I disobey G-d and his Messenger, you owe me no allegiance."

This exemplifies that all power needs restraints and reciprocity with those dependent upon its power- for server and served are dependent upon one another . All power needs restraints- even in Eden, some trees were off-limits. Corporations today forget about limits and try to master and have dominion over the earth. Mankind is but a "keeper/servant," a "caliph" of G-d. We're not entitled to the land, we are just visitors here, it's under our temporary stewardship/guardianship/custodianship.

Yasiin Bey "Fear Not of Man"