Rabbi Dr. Abraham Twerski, in his Smiling Each Day, tells of a Jewish community composed of many different religious sects, each one adhering to its own rabbi's authority. At one point a dispute erupted, mushrooming to such an extent that an outside sage was imported to resolve the strife.
This objective authority interviewed the various sides and investigated the issue at length before proposing a solution. When he finally presented an idea, though, one of the interested rabbis rejected it. He tried an alternative proposal, but another participant shot it down. A third approach was similarly demolished. Finally, he threw up his hands in exasperation and declared, "Now I understand why Avraham asked G-d regarding Sodom (Genesis 18:24), 'If there are fifty tzaddikim [righteous people] in the city, won't you desist from destroying it?' Avraham's logic was simple: If there are fifty tzaddikim in the city, they will make sure to bring it to ruin themselves; there is no need for You to intervene!"
The lesson of the story, to me, is that people pursuing righteous goals sometimes forget that they have homes, families, and a world to maintain, and that shalom in that home, family and world must be given greater priority than our other pursuits.
The Talmud (Shabbat 23b) seeks to educate this forgetful Jew, declaring, "It is obvious that a Jew who must choose to spend on either the lights of Shabbat or the lights of Chanukah should spend on the lights of Shabbat, for the sake of the peace they will provide for the home." The core purpose of our Shabbat candles is to illuminate our homes in a dignified way, so that people will be able to enjoy Shabbat in peace, without tripping over obstacles and squabbling with each other. This goal is deemed so important that it even overrides the imperative to publicize Divine miracles through the lights of Chanukah.
This law is remarkable in light of the fact that the minimum length of time required for the lights of Chanukah to burn is just thirty minutes. We are talking about reducing the fuel for one's Shabbat lamp by only thirty minutes – and even that brief length of time is considered so important that it trumps the Chanukah lights. Judaism decrees that it would be better to omit all thanks for the Divine miracle than to have a home in pain for thirty minutes.
The home exists on multiple levels; there is the literal house, the broader family, and the still-broader community. On each level, we need to preserve our shalom bayit, the peace of our home, lest people be pained. On each level we must remember the Divine mandate: Without the lights of Shabbat, one might as well not have the lights of Chanukah. First we build community and create shalom, and then we are able to celebrate Chanukah and thank G-d for the miracles. May we merit to have both parts, the shalom and the gratitude to G-d, in our homes.