'Hevel," literally a vapor - the transparent, fleeting exhalation of breath - is an unlikely word to sum up the intense period of the Jewish calendar that ends this Shabbat with Shabbat Bereishit. Yet it appears in the Yom Kippur liturgy, serves as the main theme of Ecclesiastes, which we read on Succot, and reappears in this week's Torah reading as the name of a hapless son (Abel) of Adam and Eve. Why is hevel such an important theme at this time of year? Let us briefly examine each of these occurrences of the word to see if we can find a connecting thread. During the closing amida prayer on Yom Kippur, the liturgy juxtaposes two glaringly opposite characteristics of the existential nature of the human being. First it asks, "What are we? What meaning have our lives?â€¦ What is our power?â€¦ What can we say before You, Lord our God, since all the great heroes are as nothing compared to You?... Most of their deeds are empty voids; the days of their lives are as vapor (hevel) before You. The difference between humans and animals is naught (ayin in Hebrew) because everything is vapor (hevel)." Then the liturgy completely switches gears and declares, "You have separated and distinguished the human from the beginning, recognizing his ability to stand before You." The stark contrast between the human being who is no different from a beast and the human being chosen from all other creatures to stand in the Divine presence leaves us trying to ascertain the true existential nature of man. The mystery is increased by Ecclesiastes, in which there is a constant refrain: "Vapor of vapors, vapor of vapors. The whole of life is vapor." Finally, the second son of Adam and Eve is named Hevel, or vapor - certainly referring to the briefness of his life, snuffed out by his brother Cain. Abel never married and did not have progeny. I believe that an understanding of the fundamental distinctions in the respective lifestyles and life values of these first siblings will explain the truest meaning of hevel. The Bible tersely defines each of these young men in terms of their occupations: "And Abel was a shepherd, whereas Cain was a tiller of the earth" (Genesis 4:3). Abel is mentioned first - perhaps because a shepherd, who lives off the wool and milk of living sheep, preserves and nurtures life, leaving plenty of time for meditation with the Divine, appreciation of nature, and communication of traditions and values to the next generation. None of this would apply to the tiller of the soil, whose backbreaking work often takes advantage of animal labor, exhausts the natural nutrients of the earth and rarely leaves time for cultural or religious pursuits. And even though Abel's life may have been all too brief and transitory, he nevertheless influenced subsequent generations: Jabal (his great-grandnephew, whose name is alliterally linked to Abel) "who was the first to dwell in tents and breed cattle, and Jubal, who was the first to handle the harp and flute" (Gen. 4:20-21) - both occupations of the spirit rather than mere materialistic aggrandizement. Moreover, all three names (Jabal, Jubal and Abel) are linked to yovel, the Jubilee year, the millennium, the ultimate period of peace and redemption. It is undoubtedly from this perspective that the Zohar maintains that King David, progenitor of the messiah, was a transmigrated soul (gilgul) of, or a repair for, Abel. Fascinatingly David was also a shepherd in his youth and a gifted musician who played the lyre and composed the Psalms. Allow me one more leap of exegesis to complete the picture. The Bible describes how God took dust from the earth and breathed into it the breath, or "vapor," of life, thereby forming a human being - an animal creature with the internal spark of the Divine (Genesis 2:7). The word yovel also means shofar, ram's horn, into which the human being exhales his vapor in a symbolic commitment to uplift and inspire the animal world, and especially his animal self, with the essential eternity of the Divine. We may live brief lives, akin to vapor. Nevertheless, we have the ability to communicate, to exhale and express our Divine spirit, and thereby influence subsequent generations to achieve redemption. Indeed, as recited at the end of Yom Kippur, "the difference between man and beast is Eternity [ein-sof], for everything lies in the vapor of human, humane expression [hevel]." The writer is the founder and chancellor of Ohr Torah Stone Colleges and Graduate Programs, and chief rabbi of Efrat.