The end of Sefer BeMidbar contains many interesting instances of leadership. We see one of them in Perek 32. The Pasuk reads "Nekom Nikmat Bnei Yisrael MeEit HaMidyanim Achar Tei’aseif El Amecha," "Avenge the children of Israel of the Midianites; afterwards you will be gathered unto your people" (BeMidbar 31:2). Hashem is telling Moshe to take revenge on the Midyanites. When Moshe fulfills this command, however, the Pasuk reads, "VaYishlach Otam Moshe Elef LaMateh Latzva Otam VeEt Pinchas Ben Elazar HaCohein LaTzava UChlei Hakodesh VaChatzotzrot HaTeru’ah BeYado," " And Moshe sent them, a thousand of every tribe, to the war, them and Pinchas the son of Elazar the Kohen, to the war, with the holy vessels and the trumpets for the alarm in his hand" (31:6). It seems that Moshe isn’t carrying out Hashem’s word; instead, he sends Pinchas to do it. Why does Moshe not fulfill God's direct command to him? Additionally, why is Pinchas picked over any other person in the nation?
Rashi on this Pasuk provides an answer to our second question. He asks why, specifically, did Moshe not pick Elazar, the Kohen Gadol? He answers that Pinchas was more fit for the job because he killed the Midyanite woman, Kozbi Bat Tzur, who committed adultery with the leader of Shevet Shimon, Zimri Ben Salu. Since he began the Mitzvah, he was chosen to conclude it. Moshe sent him specifically to take vengeance against the people of Midyan based on the principle that “HaMatchil BeMitzvah Omrim Lo Gemor,” one who begins a Mitzvah is told to finish it, and that he was avenging one of his ancestors.
Rashi also offers a second explanation. He suggests that Pinchas wanted to avenge his ancestor, Yosef, who was sold by the Midyanim into slavery. Rashi learns that Pinchas was from Yosef based on the fact that Elazar took a wife from the family of Putiel, another name for Yosef.
Now that we understand why Pinchas was appropriate for the job, the Midrash explains why Moshe deferred on God’s commandment. Moshe felt that he should not personally wage war against Midyan because when he fled from Par’oh in Egypt, he ran and found safety in Midyan. He felt gratitude toward Midyan, as he grew up and started a family there. We first see Moshe's sense of gratitude in his days in Mitzrayim. Hashem commanded Aharon to hit the Nile for the plagues of blood and frogs because the Nile saved Moshe when he was a baby, and therefore, he needed to show gratitude towards the Nile. Moshe reasoned that God wouldn’t want him to deny Midyan this gratitude, as the principle in Sefer Mishlei states “Deracheha Darchei No'am VeChol Netivoteha Shalom," "Her ways are of pleasantness and all of her paths are peace" (Mishlei 3:17). The Torah acts gently and therefore Moshe had to show gratitude by sending Pinchas and not going himself.
Rav Abraham J. Twerski says that we can take a lesson from Torah which demonstrates the utmost sensitivity and consideration. Unfortunately, many people do not show the proper gratitude, as they feel it shows dependence and weakness.
Rav Eli Mansour points out the importance of gratitude in our prayer. During Chazarat HaShatz, we say Amein after the Chazan recites each of the Berachot. For the Berachah of Modim, the Berachah of gratitude, however, merely answering Amein is not enough. We must get up, bow and say our own thanks in the form of Modim DeRabbanan. This is another illustration of the importance of gratitude. The lesson we can learn from Moshe in this week’s Parshah is that we need to learn take this blow to our pride and show gratitude, even if it means passing up on the honor of fulfilling a direct commandment from Hashem.