In two paragraphs, the Aleinu concentrates a basic tension in Judaism: the tension between the particular ─ Israel’s special relationship with God ─ and the universal, the faith that all of humanity will someday fully recognize the one God. In its final form, the Aleinu dates back to the third century, but has an older history perhaps as far back as the Babylonian and Persian exiles of the Sixth and Fifth Centuries BCE. An earlier form was probably recited during the Temple service. The Aleinu served not only as a rejection of ancient paganism, but also as a counterpoint to the worship of powerful kings and emperors common in those times.

In medieval siddurim, the Aleinu was placed in the Rosh Hashanah liturgy, with the shofar blowing or the musaf service, and it was directly associated with the proclamation of divine sovereignty at the beginning of the new year. But it became so popular by the Renaissance era that the Aleinu became standard near the end of every service and has appeared that way in printed prayer books ever since.

Customs vary for how much of the Aleinu is recited aloud. It is common to sing the first paragraph together, then recite the second paragraph in a low voice, singing together aloud again for the last line, “V’ne’emar ....” The leader generally gives the Community proper cues as to what to sing together and what to recite individually.


Service Section: Aleinu 
Source: http://opensiddur.org/wp-content/uploads/2014/03/Havurah-on-the-Hill-Siddur-on-the-Hill-for-Friday-Night-Vilna-Shul-Boston.pdf