Means of Deception
The Torah's reference to Eisav's garments as "חֲמׁדוֹת" - translated as "coveted"-carries deep significance. It characterizes Eisav's very nature, a desire for things that did not rightfully belong to him. This propensity for coveting extended even to the clothing he wore, suggesting that even his garments were imbued with his negative traits.
Yaakov had worked diligently on his character, refining it to the point where he found himself incapable of uttering a falsehood. As the situation called for deceit to secure his father's blessings, Yaakov had to temporarily embody some of Eisav's characteristics. By donning Eisav's garments, he was essentially aligning himself, albeit momentarily, with the negative traits that Eisav personified, enabling him to effectively mislead Yitzchok.
This method taken by Yaakov is captured in Yitzchok's reaction upon realizing the truth. He told Eisav: "בָּא אָחִיךָ בְּמִרְמָה וְיִּקַּח בִּרְכָתֶךָ" - "Your brother has come with deception and taken your blessing." Notably, Yitzchok did not directly accuse Yaakov of deceiving him. Instead, he said that Yaakov "came with [means of] deception", highlighting that his son had to cloak himself in Eisav's negative traits to carry out the subterfuge.
(טו כז חתם סוֹפֶר ד"ה הֲלֹא אָצַלְתָּ)