The word used for the shofar-blast in the Torah is "terua," which the Aramaic Targum renders as "yevava" — and the Gemara in Rosh Hashanah 33b anchors that word directly to the pasuk in Shoftim describing Sisera's mother: "Through the window she looked forth and wailed [vateyabev], the mother of Sisera" (Shoftim 5:28), using her cry of grief as the very definition of the shofar's sound.
Because the Gemara in Rosh Hashanah 33b records a dispute over whether that primal cry is a moan (shevarim) or a whimper (teruah) or both, the Shulchan Arukh (Orach Chayim 590:1–4) rules that we must cover all possibilities and blow three distinct sets — TaSHRaT, TaSHaT, and TaRaT — so that no interpretation of Sisera's mother's wail is left unfulfilled.
The 100-blast total is tied explicitly to the same figure: the Tur (Orach Chayim 590–592) cites the Arukh, who writes that those who are strict blow 30 blasts seated, 30 in the silent Musaf, and 30 in the cantor's repetition — corresponding to the 100 cries that the mother of Sisera cried — with a final 10 completing the count at the close of the service; the Kaf HaChaim (Orach Chayim 592) transmits this same passage from the Arukh word for word, and the Mishnah Berurah (592:4–5) records that the practice of completing the count to 100 is accomplished by adding a final TaSHRaT, TaSHaT, TaRaT after the concluding hymn.
Resisei Layla (46:3) probes why specifically Sisera's mother's cry was chosen as the archetype, explaining that all the power of the yevava was embodied in her, and that her wailing — over the loss of whatever good was latent even in Sisera — expressed the deepest possible shattering of vitality, making her cry the most intense model for the broken sounds of the shofar.
The Gemara in Rosh Hashanah 16a gives the broader theological frame: God commands Israel to sound the shofar on Rosh Hashanah so that Kingships, Remembrances, and Shofarot rise before Him — the shofar being the instrument through which Israel's memory ascends to God for good — and Rabbi Abbahu adds there that the ram's horn specifically recalls the Akeidah of Yitzchak.
The Sefat Emet (Rosh Hashanah 5658) adds a kabbalistic dimension drawn from the Zohar, explaining that teruah and shevarim are broken, interrupted sounds because the attribute of judgment must itself be broken and divided, so that from severity, threefold kindness is generated — giving the fragmented cry of Sisera's mother a redemptive structural role within the shofar service.