Bava Batra 327:1

ואם תאמר מוחק וחוזר ומוחק אינו דומה נמחק פעם אחת לנמחק שתי פעמים

If, however, it is objected<span class="x" onmousemove="('comment',' Lit., 'thou wilt say'. ');">¹</span> [that, since the writing on the document had been] erased [once, it might] be erased again,<span class="x" onmousemove="('comment',' And, consequently, while leaving the signatures on the first erasure, the text above them could be erased again. and on this second erasure a forged text might be substituted for the original! ');">²</span> [it may be replied that anything which] has been erased once is not like [that which] has been erased twice.<span class="x" onmousemove="('comment',' The forgery would be discovered by comparing the signatures which appear on a first erasure with the text appearing on a repeated erasure. ');">³</span>

וליחוש דלמא שדי דיותא אמקום עדים מעיקרא ומחיק ליה דכי הדר מחיק ליה להאי הוה ליה אידי ואידי נמחק שתי פעמים

But [is there no cause] to apprehend that ink might first be poured on the place of the witnesses,<span class="x" onmousemove="('comment',' I.e., on the lower section (corresponding to the place of the witnesses) of a paper which has been once erased from top to bottom. ');">⁴</span> and this<span class="x" onmousemove="('comment',' The ink poured. ');">⁵</span> would be erased,<span class="x" onmousemove="('comment',' And thus the witnesses, not suspecting that the section where they append their signatures had been erased twice, whereas the upper section only once, would be signing on a double erasure. ');">⁶</span>

אמר אביי קסבר רב אין העדים חותמין על המחק אלא אם כן נמחק בפניהם

so that when the text<span class="x" onmousemove="('comment',' Lit., 'to that'. ');">⁷</span> is subsequently erased<span class="x" onmousemove="('comment',' from the upper section, and a forged text substituted. ');">⁸</span> the lower and the upper sections would represent<span class="x" onmousemove="('comment',' Lit., 'this and this is'. ');">⁹</span>

מיתיבי הוא על הנייר ועדיו על המחק כשר וניחוש דלמא מחיק ליה וכתיב מאי דבעי והוי ליה הוא ועדיו על המחק

a repeated erasure?<span class="x" onmousemove="('comment',' Lit., 'erased twice'; and since both text and signatures would thus appear on the same kind of erasure, the court would not be able to detect the forgery. ');">¹⁰</span> — Abaye replied: Rab is of the opinion [that] Witnesses [must] not sign on an erasure unless the erasure was made<span class="x" onmousemove="('comment',' Lit., 'it was erased'. ');">¹¹</span> in their presence.<span class="x" onmousemove="('comment',' They would, consequently, be able to satisfy themselves that the upper and lower sections of the erasure were exactly alike. ');">¹²</span>

דכתבי הכי אנחנא סהדי חתמנא על מחקא ושטרא כתב על ניירא

An objection was raised: [A deed] the text<span class="x" onmousemove="('comment',' Lit., 'it'. ');">¹³</span> [of which is written] on [clean] paper<span class="x" onmousemove="('comment',' I.e., on which nothing has ever before been written. ');">¹⁴</span> and its witnesses on an erasure is valid. Is [there no cause] to apprehend that [the text] might be erased, and any [terms] one desires substituted,<span class="x" onmousemove="('comment',' Lit., 'write'. ');">¹⁵</span>

דכתבי היכא אי מלתחת גייז ליה אי עילאי מחיק ליה דכתבי בין סהדא לסהדא

and [thus] there would result [a deed] the text<span class="x" onmousemove="('comment',' Lit., 'it'. ');">¹³</span> and witnesses of which [appear] on an erasure?<span class="x" onmousemove="('comment',' Which, as has been said, is valid! Since this would facilitate forgery, why were witnesses allowed to sign on an erasure? ');">¹⁶</span> — They<span class="x" onmousemove="('comment',' The witnesses. ');">¹⁷</span>

אי הכי אימא סיפא הוא על המחק ועדיו על הנייר פסול אמאי פסול הכא נמי נכתבו הכי אנחנא סהדי חתמנא על ניירא ושטרא על מחקא

write as follows:<span class="x" onmousemove="('comment',' Lit., 'thus'. ');">¹⁸</span> 'We witnesses signed on an erasure and the text is written on paper'. Where, [however], do they write [this]? If below,<span class="x" onmousemove="('comment',' Their signatures. ');">¹⁹</span> [surely] one [can] cut it off! If above,<span class="x" onmousemove="('comment',' Their signatures. ');">¹⁹</span>

[השתא נמי] מאי אמרת מוחק חוזר ומוחק הא אמרת אינו דומה נמחק פעם אחת לנמחק שתי פעמים הני מילי היכא דחתימי סהדי אמחקא היכא דלא חתימי סהדי אמחקא אלא אניירא לא ידיע

one [can] erase it!<span class="x" onmousemove="('comment',' And the erasure would raise no suspicion since the witnesses also are signed on an erasure. ');">²⁰</span> They write [it]<span class="x" onmousemove="('comment',' The formula, 'We witnesses etc.' ');">²¹</span> between the signatures.<span class="x" onmousemove="('comment',' Lit., between witness and witness'. Consequently it cannot be cut off without cutting away with it one of the signatures; and should it be erased, it would leave a doubly erased spot which could be easily distinguished from that of the signatures which appear on what was erased only once. ');">²²</span>

וליתי מגילתא אחריתי ולמחוק ולידמי לא דמי מחקא דהא מגילתא למחקא דהא מגילתא

If so, explain the second clause: [A deed] the text<span class="x" onmousemove="('comment',' Lit., 'it'. ');">²³</span> [of which appears] on an erasure and its witnesses on [clean] paper is invalid.<span class="x" onmousemove="('comment',' Because it is possible that the original had been erased and a forged text had been substituted for it. ');">²⁴</span> Why, [it may be asked,] should it be invalid? Let them in this case<span class="x" onmousemove="('comment',' Lit., 'here'. ');">²⁵</span>

ולקבלה לחתימות ידא דסהדי בבי דינא ולמחוק ולידמי אמר רב הושעיא אינו דומה נמחק בן יומו לנמחק בן שני ימים

also write thus: 'We witnesses signed on paper and the text [is written] on an erasure'. Would you now also reply [that as the writing] was [once] erased,<span class="x" onmousemove="('comment',' The text being written on an erasure. ');">²⁶</span> one might again erase it?<span class="x" onmousemove="('comment',' And substitute a forged text for the original. ');">²⁷</span> Surely, you said [that] what was erased once is not like that which was erased twice! — This<span class="x" onmousemove="('comment',' Lit., 'these words', that it is possible to distinguish between the two kinds of erasure. ');">²⁸</span>

ולישהייה אמר רבי ירמיה חיישינן לב"ד טועין:

[has been said in the case only] where the witnesses are signed on an erasure.<span class="x" onmousemove="('comment',' Since the two kinds of erasure appear side by side, on the same document, the contrast between them would be noticed. ');">²⁹</span> Where, [however], the witnesses are not signed on an erasure but on [clean] paper [the difference<span class="x" onmousemove="('comment',' Between a first, and second erasure. ');">³⁰</span> can] not be detected.<span class="x" onmousemove="('comment',' The contrast on the document being not that between two kinds of erasure but between an erasure and clean paper. ');">³¹</span>

רבי חנינא בן גמליאל אומר מקושר וכו': השיב רבי לדברי ר' חנינא בן גמליאל

But let any<span class="x" onmousemove="('comment',' Lit., 'another'. ');">³²</span> scroll be brought, [on which some writing could] be erased, and compared!<span class="x" onmousemove="('comment',' With the erasure on the deed. The comparison would determine whether the writing on the deed was erased once or twice. ');">³³</span> — The erasure on one scroll is not [always] like the erasure on another scroll.<span class="x" onmousemove="('comment',' One of them may be thicker than the other and would not show up the erasure as well as the other. ');">³⁴</span> Let, then, the signatures of the witnesses be accepted by the court,<span class="x" onmousemove="('comment',' Provisionally, until it had been ascertained whether the text was, or was not a forgery. ');">³⁵</span> and be erased and compared!<span class="x" onmousemove="('comment',' With the erasure on which the text of the deed is written. CF. supra note 11. ');">³⁶</span> — R. Hoshaia replied: An erasure of one day's [standing] is not like an erasure of two days [standing]. Let it stand [for some time]!<span class="x" onmousemove="('comment',' When the difference between the old, and the new erasure would disappear and comparison could be made between the erasures on the two sections of the deed. ');">³⁷</span> — R. Jeremiah replied: Precaution had to be taken [to provide] against an erring court.<span class="x" onmousemove="('comment',' Which might not think of comparing erasures and, relying on the clear signatures of the witnesses, could accept the validity of the deed. (R. Gersh.) Which might not be aware of the fact that an old erasure differs in appearance from a new one and would, consequently, accept a forged document as genuine (Rashb., cf. BaH, a.l.). Hence it was ordained that any deed the text of which appears on an erasure and the signatures of its witnesses on a clean section of the paper is invalid. ');">³⁸</span> R. HANINA B. GAMALIEL SAID: A FOLDED [DEED] ETC. Rabbi raised an objection against the statement<span class="x" onmousemove="('comment',' That a folded deed may be turned into a plain one. ');">³⁹</span> of R. Hanina b. Gamaliel: