Tractate Ketuboth page 16 in the Mishna, and Tractate Bava Metzia page 4 and page 48.

I was looking at the ideas of Rav Nachum [of the Mir] yesterday and by doing so I realized that he is saying the same thing as Rav Shach. You see I see that the Rambam wrote (in Laws of Pleas chapter 4 law 4) that when you have a lender with a document, and he says to the borrower, “You owe me the 50 in this document, and another 50 besides that,” and the borrower admits the 50 in the document, the borrower does not take an oath of admission in part because all his property is underr obligation for the loan. The natural tendency here is to say the Rambam means what the Gemara says “One does not swear on obligations on land.” That leaves the Rambam open to the question of the Raavad (in Laws of Marriage chapter 16, law 25), where he admits he owes 100 to his ex-wife, and takes an oath of admission in part even though the claim is for 200, and there is no document. Rav Nachum pointed out that the Rambam says nothing about a lien on land. Rather, he says “all his property is obligated” [like a regular loan debt. Rav Nachum wrote hat the Gemara gave a few answers to a question and one of the answers was this that one does not swear on a lien on land. Rav Nachman suggested that the Rambam rejected that answer. and in a different way i realized that this was exactly what Rav Shach was saying. For Rav Shach answered the obligation is not on the land alone but also on his body. I was curious about this answer a long time because it does not seem to make sense. after all liens on land are obligations on the debtor. Then I realised that Rav Shach is saying the same thing as Rav Nachum [without the part that the Rambam rejected the claim about a lien on land, but it being implied in his answer.] and why would the Rambam reject that answer? Because it contradicts what the gemara already established many times that one does not take an oath on land--------------------------I was looking at the ideas of רב נחום[of the מיר] yesterday, and by doing so I realized that he is saying the same thing as רב שך. You see I see that the רמב’’ם wrote (in Laws of Pleas, chapter 4 law 4) that when you have a lender with a document, and he says to the borrower, “You owe me the 50 in this document, and another 50 besides that,” and the borrower admits the 50 in the document, the borrower does not take an oath of admission in part because all his property is under שיעבוד for the loan. The natural tendency here is to say the רמב’’ם means what the גמרא says “One does not swear on שיעבודים on land.” That leaves the רמב’’ם open to the question of the ראב''ד (in Laws of Marriage chapter 16, law 25), where he admits he owes 100 to his ex-wife, and takes an oath of admission in part even though the claim is for 200, and there is no document. רב נחוםpointed out that the רמב’’ם says nothing about a שיעבוד on land. Rather, he says “all his property is obligated” [like a regular loan debt. רב נחוםwrote That the גמרא gave a few answers to a question, and one of the answers was this that "One does not swear on a שיעבוד on land." רב נחום suggested that the רמב’’ם rejected that answer. I realized that this was exactly what רב שך was saying. For רב שך answered the שיעבוד is not on the land alone, but also on his body. I was curious about this answer a long time because it does not seem to make sense. After all, שיעבודים on land are שיעבודים on the debtor. Then I realised that רב שך is saying the same thing as רב נחום[without the openly saying part that the רמב’’ם rejected the claim about a שיעבוד on land, but it being implied in his answer.].and why would the רמב''ם reject that answer? Because it contradicts what the גמרא already established many times that לא נשבעים על קרקעות.