Commentaries debate the main function of Shabbat candles: they may, on the one hand, serve “oneg Shabbat”, enhancing the Shabbat experience itself, in making the meals visible (see Yoma 75b); or they may serve “kavod Shabbat”, joining in the effort to prepare for Shabbat properly, in facilitating the setting up (as emphasized by the Ri, cited in the Mordechai, II, 294). [This distinction between the natures of oneg and kavod Shabbat is codified by the Gra, Biur to O.C. 529:5].

This question may be relevant to the issue of whether the primary mitzvah action is the lighting of the candles (hadlakah) or placing them appropriately (hanachah). The Taz (O.C. 675:1) rules that for Shabbat candles, hadlakah is unimportant. This may reflect an understanding that these candles serve oneg, and thus their prime function is on Shabbat itself, when they are already lit. By contrast, the Pri Megadim, focusing on the language of the berakhah (l’hadlik), rules hadlakah is the mitzvah. Such a view is more consistent with an understanding based on kavod Shabbat.

The Shulchan Arukh (O.C. 263:4) rules that one should not light significantly before Shabbat actually begins, unless one plans on immediately accepting Shabbat; otherwise, the Shabbat connection will not be evident (see also Rama and Tosafot, Shabbat 25b, s.v. chovah. This statement is based upon a comment of the Talmud (Shabbat 23b), barring lighting that is too early or too late. However, a dispute exists as to whether this statement refers to Shabbat candles or only to those of Chanukah. The latter view seems to be that of the Rambam (Chanukah 4:5). This issue would similarly seem to depend on the above question. A related question would be that of the necessity to light if candles are already lit, and the ramifications on the obligation of the berakhah (see Tosafot, 25b, s.v. chovah).

The Rambam’s view above seemed to suggest oneg Shabbat as a focus; however, elsewhere (Hil. Shabbat 30:5) he identifies kavod Shabbat as the theme. The Brisker Rav (printed in Kitvei haGrach al haShas, p. 331) explains that the Rambam understands Shabbat candles to serve both kavod and oneg (see also Kehilot Ya’akov, Shabbat, 20, and Mishnat Ya’avetz, O.C., 75). The Tosefet Shabbat (263) suggests that in the room where the meal is, oneg is the purpose; in other rooms, it is kavod (see, however, the opposite suggestion in Arukh HaShulchan; see also Resp. Mishneh Shelomo, 18:8).

Other related issues include: having the candles lit by a non-Jew (see Magen Avraham, 263:11, and Chid. R.Akiva Eiger; Resp. Har Tzvi, O.C. 140; Resp. L’Horot Natan, VII, 120; Resp. Sh’eilat Sh’aul, 33); the status of Yom Tov candles, as some authorities (Meiri and Pnei Yehoshua, Beitzah ch. 4, and Chatam Sofer, Shabbat 111a; against the Rambam, Hil. Yom Tov 6:16) maintain there is no oneg on Yom Tov; and the status of electric lights, which may not be considered the product of human action (see Resp. Beit Yitzchak, Y.D, I, 120 and II, 31; Resp. Melamed L’Hoeil, O.C. 47; Sh’erit Yosef [Wahrman] I, 3; Resp. Achiezer, III, 60; Resp. Zeh HaYam, I, 27; Resp. Teshuvot V’Hanhagot, II, 156; Resp. Divrei Yatziv, O.C. 120).