Study Bava Batra folio 176B with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
ערב דבית דין הוא דלא בעי קנין, הא בעלמא בעי קנין.
It is only a guarantor who undertakes a loan guarantee in the presence of a court who does not require an act of acquisition; this indicates that generally, a guarantor requires an act of acquisition in order to be obligated to pay.
והלכתא: ערב בשעת מתן מעות – לא בעי קנין, אחר מתן מעות – בעי קנין. ערב דבית דין – לא בעי קנין; דבההיא הנאה דמהימן ליה – גמר ומשעבד ליה.
The Talmud concludes: And the halakha is that a guarantor who accepts responsibility for the loan at the time of the giving of the money does not require an act of acquisition; but if he accepts responsibility after the giving of the money, he requires an act of acquisition. Moreover, a guarantor who undertakes a loan guarantee in the presence of a court does not require an act of acquisition, as in return for that gratification that he experiences in that the court trusts him, he resolves to obligate himself.
Text data via Sefaria: William Davidson Edition - English and William Davidson Edition - Vocalized Aramaic, CC-BY-NC; edition provenance: Koren. Display terminology has been modernized for readability.