Responsa for Bava Kamma 83:8
אלא אמר רבא איצטריך ס"ד אמינא אנשים ולא שוורים הדומין לאנשים מה אנשים מועדין אף שוורים מועדין וק"ו לתמין דפטירי הדר כתב רחמנא בעל השור נקי תם פטור ומועד חייב
excluding oxen which could be compared with men: just as the men are <i>Mu'ad</i> so the oxen [thus exempted] must be <i>Mu'ad</i>, and <i>a fortiori</i> exemption is extended to cases of <i>Tam</i>. Thereupon the Divine Law on another occasion purposely states, <i>'The owner of the ox shall be quit'</i> [to indicate that only] in the case of <i>Tam</i> will there be exemption, whereas in the case of <i>Mu'ad</i> there will be liability [for degradation]? Now you could hardly say that this is indeed the case, for if so why not teach that, <i>'the owner of the ox shall be quit'</i> [means], according to R. Jose the Galilean, quit from compensating [both in the case of <i>Tam</i> killing] embryos and [in the case of it having caused] degradation?<span class="x" onmousemove="('comment',' But Mu'ad is liable. ');"><sup>8</sup></span>
Teshuvot Maharam
A. B must take the oath usually taken by all partners, which is administered by the hazzan holding the Scroll of the law. Although giving one's faithful word is also considered an oath, it is not as solemn as the oath administered while holding the scroll of the Law, and can not take its place.
SOURCES: Cr. 171; Pr. 606; L. 379; Mord. Shebu. 765; cf. Hag. Maim. Shebuoth 11, 3; Moses, Minz, Responsa 17.