Reference for Yevamot 218:6
ואיבעית אימא לעולם כדאמריתו מעיקרא כל האומר אין לו אלא תורה אין לו אלא תורה לא צריכא דקא מגמר לאחריני ואזלי ועבדי מהו דתימא אית ליה אגרא לדידיה קמ"ל
himself to the word of the <i>halachah</i>.<span class="x" onmousemove="('comment',' This is deduced from [H] (E.V., that strike hands) in the concluding clause of the verse cited. [H] may also bear the meaning of 'stick to', 'nail oneself to'. This will be further explained anon. ');"><sup>15</sup></span> That 'those who receive proselytes', [bring evil upon themselves, is deduced] in accordance with [a statement of] R. Helbo. For R. Helbo stated: Proselytes are hurtful to Israel as a sore on the skin.<span class="x" onmousemove="('comment',' In speaking of proselytes (Isa. XIV, 1) the word used is that of [H] (E.V., shall join) which is of the same rt. as [H] (a sore). V. supra 47b. ');"><sup>16</sup></span> 'The sureties of Shalzion [bring evil upon themselves]' because [in that place] they practice 'pull out and thrust in'.<span class="x" onmousemove="('comment',' They 'pull out' the debtor from his obligation and 'thrust in' the creditor. ');"><sup>17</sup></span>