Kabbalah for Bava Batra 156:9

<big><strong>מתני׳</strong></big> המוכר את החמור מכר את הסיח מכר את הפרה לא מכר את בנה מכר אשפה מכר זבלה מכר בור מכר מימיה מכר כוורת מכר דבורים מכר שובך מכר יונים:

thought the buyer] would require the cow for the sake of its milk, but [in the case of an] ass, what could he have meant [by mentioning 'milch']?<span class="x" onmousemove="('comment',' Surely an ass is not required for milk. ');">²³</span> It must [therefore] be concluded that he [meant] to say, '[I sell you] it [the cow] and its calf'. Why is [the foal] called Sayyah?<span class="x" onmousemove="('comment',' [H] is the term used in the Mishnah for 'foal'. ');">²⁴</span> Because it follows gentle talk.<span class="x" onmousemove="('comment',' From the root [H] = [H], talk; i.e., the gentle (lit.. the beautiful), the persuasive words of its driver. An older ass must be driven by force. ');">²⁵</span>

Derech Etz Chayim (Ramchal)