What do we learn from "Im Ein Lecha Leshalem Lamah Yikach Mishkavcha mi'Tachtecha"?
Zevachim 29b: A woman dies if her husband does not pay money 1 that he owes. She does not die if he merely delays offering vows.
R. Yonah: Even if you are rich at the time of Arvus, who knows if your wealth will remain at the time of payment. If you cannot pay, why should your Mishkav 2 be taken from you?! It is improper to trust in one's wealth - "Bote'ach b'Ashro Hu Yipol", "ha'Sa'if Einecha Bo v'Einenu" (11:28, 23:5).
Malbim: If the borrower cannot pay, you (the lender) cannot enter his house to take a security - "Lo Savo El Beiso" (Devarim 24:10), but you may enter the Arev's house. The Arev is inferior to the borrower!