Rashi (Bava Basra 9a): Ma'ase ha'Tzedakah is inducing others to give. The Gemara says that this is greater than one who gives himself ¹ . Ritva (9a) - Avodas ha'Tzedakah is giving. Its reward, "Hashket va'Vetach" is a small relief; Shalom is absolute good. "Ad Olam" applies also to Shalom.

R. Gershom (Bava Basra 9a): Avodas ha'Tzedakah is Ma'ase (inducing others to give ² ).

Radak: They are the same. Avodah is Ma'aseh; the Targum of Ma'aseh is Uvda. This is like "Ovedei Pishtim Serikos" (19:9). The matter is repeated in different words.

Radak citing Targum Yonasan: Avodas ha'Tzedakah is the work of Tzedakah.

Malbim: Avodah is greater than Ma'aseh; "Hashket va'Vetach" is greater than Shalom; also, it is "Ad Olam." Tzedakah is Mitzvos Bein Adam la'Makom. Some of them are intellectual, to fix Emunah or Musar. One does them with desire, for he understands their benefit. This is Ma'aseh. Other Mitzvos are Chukim whose reason is not known, e.g. Korbanos. One does them like a slave does his master's commands, even if he does not understand their reason or benefit. This is Avodah.