Reference for Kiddushin 8:5

יבמה תוכיח שנקנית בביאה ואינה נקנית בכסף מה ליבמה שכן אין נקנית בשטר תאמר בזו שנקנית בשטר

As for a yebamah, that may be because she cannot be acquired by deed: will you say the same of this one [a wife], who can be acquired by deed? Therefore Scripture teaches: 'when a man taketh, etc.'<span class="x" onmousemove="('comment',' That 'taking' means by money.');">⁵</span>

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