No person will refrain from defending his property
No one is willing to give up his money easily. A person is expected to defend his property and fight anyone who comes to take it from him.
("What is the reason for the law of the tunnel? The presumption is: No person will refrain from defending his property."—Sanhedrin 72a. Also: "Here the Torah teaches you: If someone comes to kill you, rise early to kill him first. This one comes to kill you, because he knows that no person will refrain from defending his property and seeing his money taken before his eyes in silence; therefore, he comes with the intent that if the owner stands up against him, he will kill him."—Rashi, Exodus 22:1)
Translation
Expression (Hebrew)
אֵין אָדָם מַעֲמִיד עַצְמוֹ עַל מָמוֹנוֹ
Definition (Hebrew)
אֵין אָדָם מוּכָן לְוַתֵּר עַל כַּסְפּוֹ בְּקַלּוּת. אָדָם צָפוּי לְהָגֵן עַל כַּסְפּוֹ וּלְהִלָּחֵם עִם מִי שֶׁבָּא לִגְזֹל אוֹתוֹ מִמֶּנּוּ.
("מַאי טַעֲמָא דמחתרת?- חֲזָקָה: אֵין אָדָם מַעֲמִיד עַצְמוֹ עַל מָמוֹנוֹ"- סַנְהֶדְרִין עַב ע"א, וְכֵן:"כָּאן לְמָדַתְךָ תּוֹרָה אִם בָּא לְהַרְגְּךָ, הַשְׁכֵּם לְהָרְגוֹ, וְזֶה לְהַרְגְּךָ בָּא שֶׁהֲרֵי יוֹדֵעַ הוּא, שֶׁאֵין אָדָם מַעֲמִיד עַצְמוֹ וּרְאֵה שֶׁנּוֹטְלִין מָמוֹנוֹ בְּפָנָיו וְשׁוֹתֵק, לְפִיכָךְ עַל מְנַת כֵּן בָּא, שֶׁאִם יַעֲמֹד בַּעַל הַמָּמוֹן כְּנֶגְדּוֹ יַהַרְגֶנּוּ"- רָשִׁ"י שְׁמוֹת כב א)