Pinchas was a zealot.
Today the words, zealot, fanatic or extremist are dirty words. But if you think about it, we are all zealots, fanatics and extremists about something; about our food, money, reputation or the honor we receive or don’t receive from others. We may even be fanatical about our favorite sports team.
We have to be choosey about our fanaticism. We have to know when and where extremism is warranted.
We have to zealots when it comes to loving and embracing our fellow Jew.
We have to be extremists when it comes to taking care of our family.
We have to be fanatics when it involves business honesty and integrity.
We have to be radical about the love and devotion to G‑d and the observance of the Mitzvot, like keeping Shabbat, kosher, giving Tzedakah et al. 
And above all, we have to be obsessed with doing one more Mitzvah, one more act of goodness and kindness to bring Moshiach and the Final Redemption that will bring genuine peace to the entire world!
The Gift of Wholeness
G‑d rewarded Pinchas for his brave act of zealotry in killing the two immorally consorting leaders, Zimri the prince of the tribe of Shimon, and Cozbi a Midianite princess. In return for this courageous deed, G‑d gave Pinchas His “covenant of shalom-peace.”
The word shalom here is written with a broken letter vav, which changes the pronunciation of the word from shalom to shalem, which means whole or complete. G‑d gave Pinchas the gift of wholeness.
Now, the simple reading of the text, that G‑d gave him a gift of peace, is understandable. Pinchas committed an act of violence and zealotry against a popular leader in the antithesis of peace. G‑d therefore compensated him with the gift of peace; that he should not be a source of strife.
Indeed, this is how Rashi (as explained by the Rebbe), answers the question of why the Torah traces his ancestry back to Aaron. It was to underscore that Pinchas’ act was motivated not by hatred or a violent temperament but rather by the spirit of peace and love inherited from his grandfather Aaron.
While Pinchas committed the ultimate violent act by killing two people, the Torah wants us to know that he did it out of love for G‑d and the Jewish people, who were dying as a result of their degeneration into immorality with Zimri as their role model.
However, now that we must render the word shalom as if it said shalem-complete, what was it about Pinchas’ act that warranted the reward of completeness?
Why a Spear?
To answer these questions let us return to the narrative of Pinchas’ action at the end of last week’s parsha.
The Torah states that Pinchas took a romach-spear to kill Zimri and Cozbi.
Since the Torah does not waste words on irrelevant details, we must say that its recounting that Pinchas used a spear to kill Zimri and Cozbi serves as a powerful hint that sheds light on his motives.
To understand the significance of the word romach, we will need to refer to the level of Torah interpretation that uses gematria-numerology.
Romach has the numerical equivalent of the name Abraham, which is 248. There are also 248 positive commandments in the Torah and the Shema has 248 words.
What do all these items, the spear, Abraham, the positive commandments and the Shema have in common?
They are all associated with the trait of love.
Abraham was the ultimate lover of G‑d and people. His whole life was dedicated to performing acts of loving-kindness. He personified love.
The 248 positive commandments likewise are expressions of our love for G‑d. We are willing to make our actions conform to His will.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
The Shema begins with an affirmation of our faith in one G‑d which is followed by the commandment to love G‑d with all our hearts, soul and might.
The fact that these symbols of love are all related to Pinchas’ spear indicates that his zealotry was motivated by a profound love for G‑d and the Jewish people, in the spirit of Abraham, the Shema and the 248 commandments.
Destroying Evil Versus Pruning Evil
However, we must probe deeper into this matter. While the word romach-spear shares a numerical equivalency with the other symbols of love the spear itself appears to be a questionable symbol of love.
Chassidic thought, however, views the spear as the force of love for G‑d that destroys the negative loves and passions we have. The way we achieve this goal is through the recitation of the Shema, which generates a powerful love for G‑d.
Before we recite the Shema, however, we chant a section of the morning prayer containing a selection of Psalms called pesukei d’zimra, verses of song. But this also can be translated as verses of “cutting or pruning,” because by reciting and meditating on the songs that extol the greatness of G‑d we cut away at the spiritual weeds and overgrowth that stand in the way of our loving relationship with G‑d.
The pesukei d’zimra is likened to a sword which can be used to cut back the undesirable growths. But, as weeds everywhere, they eventually grow back.
However, the Shema is likened, as mentioned above, to a spear, which penetrates more forcefully into the negative forces and destroys them totally.
Zimri and Cozbi: Fleeting Love
It is noteworthy that the name Zimri is related to the Hebrew word Zemer, which has a dual meaning: song and pruning.
On an allegorical level we may suggest that Zimri represents the preliminary level of love for G‑d that can only accomplish a temporary, superficial change which does not endure. Thus, Zimri consorts with Cozbi, which means falsehood. Only the romach-the spear, the 248 words of the Shema, can penetrate deep enough into our Animal Soul to eradicate all of its negative traits.
The Shema is not just about knowing G‑d’s greatness. It’s about His exclusivity. When we say that G‑d is “one,” we do not mean simply to negate belief in polytheism.  More significantly, we are saying that all which exists in our world is an extension of, and incorporated within, G‑d’s being. When we are able to internalize this mediation, it removes every vestige of ego and passion for unworthy things.
We can now understand the meaning of G‑d’s gift of shalem, completeness, to Pinchas. Without Pinchas’ spearing of Zimri and Cozbi, i.e., without the passion based on the principles of the Shema and the oneness of G‑d (romach-spear), our passion for G‑d is limited to the peripheral pruning of evil (Zimri) that does not endure (Cozbi). Our spiritual state might be good but it is not complete. Thus Pinchas, with his “spear,” created a state of spiritual completeness.
Get Your Spear and Bow and Arrow Ready!
Pinchas, our Sages teach us, is the same person as Eliyahu, the prophet who heralds the coming of Moshiach.
This suggests that before the Messianic Age begins, we are empowered to go beyond the pesukei d’zimra stage of love for G‑d.  We can even reach the higher and more authentic and enduring form of the Shema, which is likened to the spear.
In truth, although the Shema brings us to a higher and deeper love, it is still not the climax. The zenith is the Shemonah Esrei, the 18 Benedictions, also known as the Amidah, the standing prayer. This prayer is compared to a bow and arrow, which can even reach enemies, i.e., forces of evil, that are remote and which one cannot even see. It can reach out and destroy even the subtlest forms of evil that lurk way beneath the surface.
The Rebbe revealed to us that we are living in the final generation of Galus and are poised to be the first generation of Geulah-Redemption. As such, all of the most subliminal forces of evil (and correspondingly, of goodness) are now exposed so that the most elusive forms of evil can be utterly destroyed.
We are living in the Shema and Shemonah Esrei era!