Bava Batra page 3a. Rambam laws of neighbors chapter 2 halacha 10

I would like to answer the question I asked yesterday about the approach of Rav Isar Meltzer about the Rosh [rav ]. The Rosh holds with this courtyard (that does not have four cubits for each of the partners) they agree to divide by exchange. That in itself explains the Rosh entirely. With an exchange, neither has to say, “Go and acquire” and you only need one to go and take hold of his half. so there is no ambiguity about the Rosh. The question then what is the reason for the Rambam? Why both need to take possession, but neither needs to tell the other “Go and acquire?” For this both Rav shach and Rav Isar meltzer explain the reason is that to the Rambam this is not acquisition by exchange, but rather division of what both already own. Therefore, neither need to say “Go and acquire,” however both need to take possession of their half. Now you might ask why do they not need to say, “Go and acquire?” Because you only need that when one sells property to the other, and the other takes possession not in front of the seller. That goes according to the idea of Rav Isar Meltzer that to say “Go and acquire” means a direct command which we would need in case of acquisition. But even without that command, there is still an implicit agreement to acquire. But if in those words there is only the meaning of agreement to acquire, then even with division of property we would need one to tell the other “Go and acquire.” ______________________________________________________________________________________________________________________________________________ I would like to answer the question I asked yesterday about the approach of רב איסר מלצר about the רא''ש. The רא''ש holds with this courtyard (that does not have four cubits for each of the partners), they agree to divide by exchange. That in itself explains the רא''ש entirely. With an exchange, neither has to say, “Go and acquire” and you only need one to go and take hold of his half. so there is no ambiguity about the רא''ש. The question then what is the reason for the רמב''ם? Why both need to take possession, but neither needs to tell the other “Go and acquire?” For this both רב שך and רב איסר מלצר explain the reason is that to the רמב''ם this is not acquisition by exchange, but rather division of what both already own. Therefore, neither need to say “Go and acquire,” however both need to take possession of their half. Now you might ask why do they not need to say, “Go and acquire?” הטעם הוא Because you only need that when one sells property to the other, and the other takes possession not in front of the seller. That goes according to the idea of רב איסר מלצר that to say “Go and acquire” means a direct command which we would need in case of acquisition. But even without that command, there is still an implicit agreement to acquire. But if in those words there is only the meaning of agreement to acquire, then even with division of property we would need one to tell the other “Go and acquire.” הברצוני לענות על השאלה ששאלתי אתמול לגבי גישתו של רב איסר מלצר לגבי הרא''ש. הרא''ש מחזיק בחצר זו (שאין בה ארבע אמות לכל אחד מהשותפים), הם מסכימים לחלוקה לפי החלפה (קנין חליפין). זה כשלעצמו מסביר את הרא''ש לגמרי. עם החלפה, אף אחד לא צריך להגיד "לך ותרכוש" (לך חזק וקני) ואתה צריך רק אחד שילך ויאחז בחצי שלו. כך שאין אי בהירות לגבי הרא''ש. השאלה אם כן מה הסיבה לרמב''ם? למה שניהם צריכים להשתלט, אבל אף אחד לא צריך להגיד לשני "לך ותרכוש?" לשם כך מסבירים גם רב שך וגם רב איסר מלצר הסיבה היא שלרמב''ם זו לא רכישה על ידי החלפה, אלא חלוקה של מה שכבר יש לשניהם. לכן, אין צורך לומר "לך ורכש", אולם שניהם צריכים להשתלט על המחצית שלהם. עכשיו אתה יכול לשאול מדוע הם לא צריכים לומר, "לך לרכוש?" הטעם הוא כי אתה צריך את זה רק כאשר אחד מוכר נכס לשני, והשני משתלט לא מול המוכר. זה הולך לפי הרעיון של רב איסר מלצר שלומר "לך ורכש" פירושו פקודה ישירה שנצטרך במקרה של רכישה. אבל גם בלי הפקודה הזו, עדיין יש הסכמה מרומזת לרכישה. אבל אם במילים האלה יש רק משמעות של הסכם לרכוש, אז גם עם חלוקת רכוש נצטרך שאחד יגיד לשני "לך ותרכוש