The Friday night synagogue service is actually two separate services, Kabbalat Shabbat (Greeting the Shabbat) and Maariv (Evening Service). Those attending Friday night services in traditional synagogues (but not Chassidic) will notice a brief interlude between the two that is filled with subdued mumbling. This is the recitation of Bameh Madlikin, the second chapter of the Mishnah tractate Shabbat.
Bameh Madlikin literally translates as “With what may we light?” This chapter deals, primarily, with the appropriate kindling material to be used for the Sabbath lights. While candles are commonly used today, in Talmudic times oil lamps were the norm. The Mishnaic discussion includes what type of wick (one made of a material that burns evenly) and oil (those that burn well and are not malodorous) may be used. There is also a discussion of when one may possibly extinguish a flame (e.g. fear of bandits) and when not (to save a few cents).
The seventh section of the chapter notes that “a person must say three things in his home on the eve of Shabbat just before dark: ‘Have you tithed? Have you prepared the eiruv? Kindle the [Shabbat] lights’...” Most congregations recite this section before the evening Maariv service, while others have the custom of reciting Bameh Madlikin after the evening service or during the meal itself so as to fulfill the mitzvah of studying the laws of Shabbat.