Dvar Torah based on a sicha in Likutei Sichos chelek daled:

In תשי"א, the year the Rebbe accepted the נשיאות of the Chabad movement, he farbrenged with his chassidim on the yahrtzeit of his father, ר' לויק, which is on כ' אב. During the farbrengen the Rebbe mentioned that the only time that כ' אב is mentioned in ש"ס is in מסכת תענית. It states there that קרבן העצים took place nine times a year. This began at some point when there was a wood shortage in the בית המקדש. Several families took it upon themselves to sponsor the wood for the entire upcoming year. From that year onward each family continued sponsoring the wood on the same date as the original year. On that specific day they would celebrate with a יום טוב in the בית המקדש. Even when the בית המקדש had a sufficient wood supply the kohanim would still use that family’s wood for all of the קרבנות of that day. There was a particular family that would sponsor the wood every year on כ' אב. There is a מחלוקת between ר' יוסי and ר' מאיר regarding their name. According to ר' מאיר it was בני דוד בן יהודה. According to ר' יוסי it was בני יואב בן צרויה. We know everything in תורה is אמת and therefore we can't argue on something that is factual. So how can this מחלוקת take place in the first place and how can it be resolved? The answer is that this family descends from both יואב and דוד.

What then is the מחלוקת? It isn't really regarding the family's name. It is really regarding whose זכות granted them the נתינת כח, the drive to be so kind. Does this kindness come from דוד המלך or from יואב? But why would they need a נתינת כח, a drive just to sponsor wood? What's really the big deal, the big fuss? The גמרא explains that you are not allowed to chop wood for the Beis Hamikdosh after חמשה עשר באב because after that date the sun's strength weakens, תשש כוחה של חמה. We are therefore concerned that the wood would stay moist, thereby making the wood פסול for use in the Beis Hamikdosh. So the family who brought the wood to the Beis Hamikdosh on כ' אב had to take extra precautions and preparations, i.e. planning, storing, cutting etc., which was more than the other families who brought wood had to do. And what was all the wood for? To enable anyone who needed to to bring a קרבן, even for קרבן חטאת for an עבירה. They had compassion for all Yidden.

Who do these good middos come from? Dovid or Yoav? In Gemara Sanhedrin it states that if not for Dovid Hamelech's learning Yoav would not have been successful in his wars. And if not for Yoav going to war Dovid Hamelech would not have been able to learn Torah. They both did their job with complete devotion and mesiras nefesh. They put their neshama into it completely.

Reb Meir’s name means to bring light and therefore he focuses on the greatness of Torah. Dovid's way of serving Hashem was to learn Torah with complete bittul; he gave himself to the Torah completely. That's why Reb Meir focuses on the fact states that the family who brought wood on כ' אב descends from Dovid, because they committed themselves to pay for the wood and were devoted to do all the necessary preparations. They learned this element of bitul, self-nullification, giving of themselves completely, from Dovid.

Reb Yossi's name (יוסי) is gematria 86, the same gematria of the name Elokim and the word hateva (הטבע). Reb Yossi focused on the physical world. He therefore focuses on Yoav, whose job was to make a דירה בתחתונים, a dwelling place for Hashem down here in this natural world. The lesson we can learn is that when a person has something that can benefit others he should be ready to give it away happily, even if that person is a sinner. When you act in such a manner your children will learn to put themselves aside to do a favor for another. And when we raise a generation like that they will correct the reason for חורבן בית המקדש. The בית המקדש will be built בקרוב ממש and bring the גאולה האמיתית השלמה, the complete and true redemption with Moshiach now. My father, whose יארצייט is today, כ' אב, like Reb Levik, used all his כוחות הנפש to serve 'ה, even when he was very weak. He would specifically leave his תפלין in 770 so he would have to daven in shul even when it was very difficult for him. He would look for every Jew he could find in the hospital, doctor or patient, to be מזכה them with mitzvas tefillin.

He would insist on building the סוכה in his own perfect way and having guests even when he was extremely weak and couldn't eat much himself, because, after all, that's what gave him כח, strength, and brought him joy and happiness. He had complete מסירת נפש for Hashem’s מצוות and for a fellow Jew in need.

It's השגחה פרטית that he shares the יארצייט with Reb Levik, the Rebbe's father. Reb Levik, the Rav of Yekaterinoslav, would guide his fellow אידן in the light of תורה and מצוות in the dark and dangerous days of the Communist regime. With the Russians watching his every move like hawks, he remained fearlessly bold and unafraid in his commitment to keeping אידישקייט alive.

In 1939, after 30 years of leadership, he was arrested and sent to גלות in Chilli, Kazakhstan. Living in a remote village under very difficult conditions Reb Levik's health began to deteriorate. Through hunger, drought and illness he refused to be consumed by darkness. With help from his wife, Rebbetzin Chana, he continued writing ספרים in the most difficult circumstances. His אמונה and מסירת נפש were tremendous.

For many years my father, Reb Chaim Avraham Tzion a”h ben Baruch, fought a very brave battle against a very difficult illness. Terrible pain, weakness, pessimism and negative medical advice would not damper his אהבת ישראל for his fellow Yid or his strong אמונה and בטחון in Hashem and the Rebbe, that miracles can and do happen. והקיצו ורננו שוכני עפר יחי אדונינו מורנו ורבנו מלך המשיח לעולם ועד