Bava Batra 77B

כאותה ששנינו: כותבין שטר למוכר אף על פי שאין לוקח עמו. כיון שהחזיק זה בקרקע ⁠– נקנה שטר בכל מקום שהוא; וזו היא ששנינו: נכסים שאין להן אחריות נקנין עם נכסים שיש להן אחריות, בכסף ושטר וחזקה!

This is like that which we learned in a Mishnah (167b): A scribe may write a bill of sale for the seller even if the buyer is not with him when the seller presents his request. In a case of this kind, once this buyer takes possession of the land the deed is acquired wherever it is. And this is that which we learned in another Mishnah (Kiddushin 26a): Property that does not serve as a guarantee, i.e., movable property, can be acquired together with property that serves as a guarantee, i.e., land, when the land is acquired by means of giving money, or by means of giving a document, or by means of taking possession. This shows that a bill of sale can be transferred without any act of acquisition performed for the document, and certainly through words, which presents a difficulty to Rav Ashi’s opinion.

אגב שאני; דהא מטבע ⁠– דלא ניקני בחליפין, ואגב ארעא ניקני.

The Talmud answers: Acquiring a bill of sale by means of acquisition of land is different, as it is similar to acquisition through an item, not by means of words. The reason is that money, which cannot be acquired through symbolic exchange, a pro forma act of acquisition effecting the transfer of ownership of an item, nevertheless can be acquired by means of land.

כי הא דרב פפא הוו ליה תריסר אלפי זוזי בי חוזאי, אקנינהו ניהליה לרב שמואל בר אחא אגב אסיפא דביתיה. כי אתא, נפק לאפיה עד תווך.

This is like that incident where Rav Pappa had deposited 12,000 dinars with bailees in Bei Ḥozai. He transferred ownership of the money in Bei Ḥozai to his agent Rav Shmuel bar Aḥa by means of the threshold of his house. The Talmud adds: When Rav Shmuel bar Aḥa came from Bei Ḥozai with the money, Rav Pappa was so happy that he was bringing him his money that he went out all the way until Tavakh to greet him.