Rashi: This is one who withholds Chesed from his colleague. The prefix Lamed is like la'Rav, la'Tzav, la'Shav. Also Mas is a verb, like Ba and Shav. He eradicates the Chesed. This is like "v'Cham ha'Shemesh v'Namas."

Ibn Ezra: This is [melting,] like "va'Yimas Levav ha'Am." One who does so to his friend, Chesed Hu ¹ ! I thought that others would help me!

Devar Eliyahu: This includes three evils. (a) He does not do Chesed with another, even if he is not his friend. (b) Even worse - he withholds Chesed from his friend, who clings to him like a brother. (c) Even worse - he withholds Chesed, even though he does not gain via this.

Malbim: He intimidates his colleague with Chesed and disgrace. Via this, "v'Yir'as Shakai Ya'azov" - he abandons Yir'as Shamayim. You said "Yir'asecha Kislasecha", to strengthen Emunah of Hashgachah and Yir'as Hashem. Why did the Nevu'ah come to you, and not to me, to whom it applies?! Therefore, I do not believe your Nevu'ah.

Devar Eliyahu #1: There are two purposes for man. (a) To fulfill "Es Elokim Yere v'Es Mitzvosav Shemor." (b) To benefit others and do Chesed with them - "Olam Chesed Yibaneh." These are two Kelalim in Torah. The entire Torah is included in "b'Chol Derachecha Da'ehu." "V'Ahavta l'Re'echa Kamocha" is a great Klal in Torah - the rest is Perushu. Hashem gave to man two great gifts corresponding to them - "u'Matza Chen v'Sechel Tov b'Einei Elokim v'Adam." If man does not have fear and Chesed, Chen and Sechel Tov are withheld from him. You know that "Ein Ezrasi Vi" - Hashem does not help me, and people do not - "v'Sushiyah Nidechah Mimeni." I am like one who does not do Chesed, and does not fear Hashem - he loses both gifts. Why do you tell me to hope for Hashem to benefit me?

Devar Eliyahu #2: This includes two evils. (a) He is not diligent to seek Yir'as Shamayim. (b) Further, when a Mitzvah comes to his hand, he abandons Yir'as Shamayim and does not do it.