Reference for Yevamot 217:17
<big><strong>גמ׳</strong></big> ומי שרי והתני בר קפרא לעולם ידבק אדם בשלשה דברים ויתרחק משלשה דברים ידבק בשלשה דברים בחליצה ובהבאת שלום ובהפרת נדרים ויתרחק משלשה דברים מן המיאון ומן הפקדונות ומן הערבונות מיאון דמצוה שאני:
UNTIL SHE IS OF AGE<span class="x" onmousemove="('comment',' And her marriage with her husband becomes Pentateuchally binding. ');"><sup>54</sup></span> WHEN THE OTHER BECOMES FREE<span class="x" onmousemove="('comment',' From levirate marriage and halizah. ');"><sup>47</sup></span> AS BEING [THE LEVIR'S] WIFE'S SISTER. R. JOSHUA SAID: WOE TO HIM<span class="x" onmousemove="('comment',' The surviving brother, ');"><sup>55</sup></span> BECAUSE OF HIS WIFE AND WOE TO HIM BECAUSE OF HIS BROTHER'S WIFE! HE MUST ALLOW HIS WIFE TO GO<span class="x" onmousemove="('comment',' He may not retain her owing to the levirate bond (cf. supra note ); R. Joshua, contrary to the opinion of R. Gamaliel, holding the view that a levirate bond does cause the prohibition of the widow's minor sister; and since the levirate bond is the result of a Pentateuchally binding marriage, the marriage with the minor, which is only Rabbinically valid, must be dissolved, ');"><sup>56</sup></span>