Reference for Bava Kamma 62:1

ראשון ודאי פושע הוא שני אגופו מחייב דהוה לו לעמוד ולא עמד אממונו פטור דא"ל האי בירא לאו אנא כריתיה

— The first was certainly [considered] careless,<span class="x" onmousemove="('comment',' [Since stumbling implies carelessness.] ');">¹</span> whilst, as to the second, he is liable for damage done by his person, [that is,] only where he [has already] had [the opportunity] to rise and did [nevertheless] not rise; for damage caused by his chattels he is [however] exempt, as he may say to him:<span class="x" onmousemove="('comment',' To the third. ');">²</span>

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