In this parashah we see that the people of Israel is heading to the Land of Israel, to undertake the conquest, for this they have to go through different nations.
These nations do not want to give him free passage, but go out to fight against Israel.
G-d tells Moses to prepare to fight against Midian, however Moses entrusts this mission to Pinchas.
If G-d commanded Moshe, why does Moshe transfer it to Pinchas?
As we see in Bemidbar 31-6: "And Moshe sent them ..... and Pinchas Ben Elazar".
Being that Moshe lived for forty years in Midian, and this nation took him in as he fled from Egypt, there he married Tziporah and had children. It was not worthy for him to fight and organize the war against Midian.
From here we learn a very important message, the recognition of the good. The Talmud in Tractate Baba Batra writes "... From the well that you drank from, do not throw stones over it..."
We observe how on several occasions this concept is repeated in the Torah.
For example, when the people of Israel were slaves in Egypt, and Moses goes to talk to Pharaoh to let them leave, after his refusal, the ten plagues begin. G-d tells Moshe that Aaron should strike the Nile River to turn it into blood, Rashi asks why Aaron and not Moshe?
Since Moshe as a baby was deposited by Miriam in the river, and the river carried him into the hands of Batya, Pharaoh's daughter, by which he was saved, it would not be worthy for the river to be turned by Moshe into blood.
In the same way, it is not right for Moses to wage war against the country that gave him refuge.
The quality of the recognition of good connects us to G-d. "...If Moshe cannot strike the river because it saved his life, how much more so if G-d gave us life and an eternal soul, which we have Him to thank infinitely...".
Rav Bejaye Ibn Pakudah, one of the great Spanish philosophers of the 13th century in his book "The Duties of the Heart" writes that "...the essence of all spiritual work is to develop the recognition of the good, because it is the quality that connects us to G-d...".
The moment we recognize that everything we have is from the Creator, this should lead us to love G-d, and to generate a relationship of union with Him.
If a person has benefited us, the moment he asks us for something, we will quickly want to please him, but it is not because we feel indebted, but because we want to help him.
This is the relationship of love that man should have with G-d, and this is what Moses teaches us when he asks Pinchas to lead the war against Midian, in his place.