(Gemara): Our Mishnah is like R. Yehudah.

(Beraisa - R. Meir): R. Eliezer says that his words take effect on a weekday, because he could write, but not on Shabbos;

R. Yehoshua says, his words take effect on a weekday, and all the more so on Shabbos (when he may not write)!

Similarly: R. Eliezer says, we can be Mezakeh for an adult, but not for a minor (who could not acquire for himself);

R. Yehoshua says, we can be Mezakeh for an adult, and all the more so for a minor!

R. Yehudah says, R. Eliezer says that his words take effect on Shabbos, but not on a weekday, and R. Yehoshua says that his words take effect on Shabbos, and all the more so on a weekday!

Similarly: R. Eliezer says that we can be Mezakeh for a minor, but not for an adult, and R. Yehoshua says that we can be Mezakeh for a minor, and all the more so for an adult!

(Mishnah - Beis Shamai): A house fell on Reuven and Levi (his father, or someone else whom Reuven inherits). Reuven's property was not enough to pay his creditors (or his wife's Kesuvah). Levi's remaining heirs (i.e. after Reuven) say that Reuven died first, so the creditors have no claim on Levi's property. The creditors say that Levi died first, so Reuven inherited Levi's property, and they can collect it. The creditors and heirs divide the disputed amount (that the creditors want to collect from Levi's property);

Beis Hillel say, we leave the property in its Chazakah (with the heirs).

(Gemara - Mishnah): If Shimon lent Yehudah and wrote a document, he can collect from Meshubadim (property that Yehudah sold after the loan). If there is no document, he only collects from Bnei Chorin (property that Yehudah still owns).

Question (Shmuel): If Yehudah gave Shimon a lien 'on property that I will acquire', what is the law?

According to R. Meir, one can be Makdish Davar she'Lo Ba l'Olam (transfer ownership of something that is not yet in the world), so surely this takes effect;

He asks according to Chachamim, who say that one cannot be Makdish Davar she'Lo Ba l'Olam.

Answer (Rav Yosef - Mishnah - Chachamim): (David brought a document saying that Moshe owes him money. Moshe showed a document that he bought land from David after the loan, and says 'surely he would not sell me property if I still owed him!') Moshe's claim is not accepted. David was clever; he sold him land so he can collect it!

Objection (Rava): Do you prove that the lender can collect land from the borrower that he bought later and is still in his possession?! This is obvious! He can collect anything that the buyer has, even the shirt off his back!

The question was whether or not Shimon can collect property that Yehudah later acquired, and then sold or bequeathed it.

Answer (Rav Chana - Mishnah): ...Levi's heirs say that Reuven died first, and the creditors say that Levi died first (so they can collect it).

If a lender cannot collect property that the borrower later bought and sold or bequeathed, even if Levi died first and Reuven inherited, they cannot collect from the heirs (who inherited from Reuven)!

Rejection #1 (Rav Nachman citing Ze'iri): The creditors do not collect due to the lien, rather because it is a Mitzvah for orphans (or other heirs) to pay the debt of their father (the one they inherited from).

Objection (Rav Ashi): The Mitzvah to pay the father's debt is from inherited land on which there was a lien. If we would say that there is no lien on this land (since Reuven acquired it after the loan), there would be no Mitzvah to pay!

(Rav and Shmuel): A loan without a document cannot be collected from one who inherited or bought from the borrower.

Rejection #2 (of Answer #1): The Mishnah is like R. Meir, who says that one can be Makneh Davar she'Lo Ba l'Olam;

The question was according to Chachamim.

Answer #2 (R. Yakov of Nehar Pekod - Mishnah): Predated loan documents are invalid. Postdated loan documents are valid.

If a lender cannot collect property that the borrower (Daniel) later bought and sold or bequeathed, why are postdated loan documents valid? Perhaps Daniel acquired property after the loan and before the date, and sold or bequeathed it. Since the date on the document is after Daniel acquired the property, Daniel's creditor will collect the property (but he is not entitled to)!

Rejection: The Mishnah is like R. Meir, who says that one can be Makneh Davar she'Lo Ba l'Olam.

Answer #3 (Rav Mesharshiya - Beraisa): Compensation for improvements: if Aharon sold a field to Kalev, and Kalev improved it, and Aharon's creditor took it, Kalev can collect what he paid from property that Aharon sold. He collects the value of the improvements only from Aharon's Bnei Chorin.

If a lender cannot collect property that the borrower later bought and sold or bequeathed, why can the creditor take the improvements from Kalev? (Since there is a lien on the land, it is as if the borrower acquired the improvements (and this was after the loan), and the creditor collects this from the buyer!)

Rejection: The Beraisa is like R. Meir, who says that one can be Makneh Davar she'Lo Ba l'Olam.

The following question applies only if you will say a lender can collect property that the borrower later bought and sold or bequeathed.

Question: If Yehudah borrowed from Shimon and then from Levi, and acquired property, does Shimon have a lien on it (to collect from one who buys or inherits from Yehudah), or Levi?

Answer #1 (Rav Nachman citing Chachamim of Eretz Yisrael): Shimon has a lien.

Answer #2 (Rav Huna and Rabah bar Avuha): They both have liens (each collects proportionally to his loan).

Ravina: At first, Rav Ashi said that Shimon has a lien. Later, he said that they both have liens.

The Halachah is, they both have liens.

Question (Beraisa): Compensation for improvements: Aharon sold a field to Kalev; Kalev improved it, and Aharon's creditor (Yakov) took it. Kalev can collect what he paid from sold property, he collects the improvements from Bnei Chorin.

Since Kalev is entitled to collect his improvements, he is like a second creditor (for this amount). Yakov should collect only half of the improvements (and Kalev 'collects' (i.e. keeps) the other half)!

Answer: Indeed, the Beraisa means that Yakov collects half the improvements.