The stormy petrel is saying, "Light is sown for the righteous, and joy for the straight-hearted." (Psalms 97:11)
Rabbi Yossi would say: The property of your fellow should be as precious to you as your own. Perfect yourself for the study of Torah, for it is not an inheritance to you. And all your deeds should be for the sake of Heaven.
Gevurah shebeGevurah (discipline and judgment within the context of discipline and judgment)
In the ninth week of Perek Shirah, the stormy petrel announces that, “Light is sown for the tzadik (righteous) and joy for the upright of heart.” (Psalm 97:11) In some years, this week falls entirely in the month of Cheshvan, while in other years it already includes the first day of Kislev, the month of Chanukah. Even in years when Rosh Chodesh Kislev does not take place this week, there is another date in it closely linked to the Maccabees: the 23rd day of Cheshvan. In the era of the Talmud, this date was quite celebrated, as it marked the removal of the stones of the Temple’s altar that had been rendered impure by the Greeks. The stormy petrel’s verse, which mentions light, seed, and protection for the righteous, is very connected to the Maccabees and to the events that took place during Chanukah, which is called the “Festival of Lights.” Miraculously, G-d made it so that the Maccabees, righteous warriors of the seed of Aaron, defeated Greece, the greatest empire of the time.
In Pirkei Avot, Rabbi Yossi states: "The money of your neighbor should be precious to you as if it were your own. Ready yourself for the study of Torah¸ as it does not come to you as an inheritance, and may all your actions be for the sake of Heaven." (II:12)
This teaching in Pirkei Avot is deeply connected with the month of Kislev and to the struggle of the Maccabees. While the Greeks admired the Torah as a philosophy, with highly practical concepts (like the idea of respecting other people's money), they tried to break our link to the Torah, as well as our personal connection with G-d. The Midrash tells us that "darkness symbolizes Greece, which darkened the eyes of Israel with its decrees, ordering Israel to, 'Write on the horn of an ox that you have no inheritance in the G-d of Israel.'”
It is also worth noting that Rabbi Yossi was himself a kohen, just like the Maccabees. Also like the Maccabees, Rabbi Yossi is called a “chassid” – extremely pious, going beyond the letter of the law to do the will of G-d.
For Rabbi Yossi, in order to follow a righteous path, it is very important to have a “good neighbor,” and avoid a “bad neighbor” at all costs. Here, a good neighbor, Shachen Tov, may be a reference to the Shechinah, which dwells among the Jewish people and in the Temple. A bad neighbor, is likely a reference to the Greeks, which tried so hard to make us assimilate and to take us away from our roots.
The combination of sefirot for this week is gevurah shebegevurah. Note that for those that are part of the Lubavitch Chassidic movement, Rosh Chodesh Kislev’s connection with gevurah shebegevurah is quite clear. The first is an openly positive one: with great strength and courage, Rabbi Menachem Mendel Schneerson, the Seventh Lubavitcher Rebbe, miraculously survived a heart attack, and returned to his home on Rosh Chodesh Kislev. On the other hand, with much sorrow, it is on Rosh Chodesh Kislev that we commemorate the day that the Chabad-Lubavitch emissaries of Mumbai, India, were killed.
The stormy petrel tells us that one of the most important steps in achieving happiness is to be a good, honest and fair person. Rebbe Nachman of Breslov teaches that one should always take note and focus of such good qualities and actions in others and in oneself. Even if these good points are small, imperfect and incomplete, they are nonetheless a cause for great joy.
 Genesis Rabba 2:4
 Likutei Moharan I:282
[Gematria Thought: The number nine is associated with the nine months of pregnancy. It is also connected to truth. If one adds the digits in the gematria of the Hebrew word for truth, emet, the total is nine. The total of the sum of the digits (also known as gematria ketanah) in all of G-d’s names is also nine, because G-d’s “seal” is truth. Nine is also three times three, a “double chazakah,” as explained in week three.
 From the writings of the Rebbe’s father, Rav Levi Yitzchak Schneerson.]