Moshiach's power comes from a girl lighting Shabbos candles

Sicha of the Lubavitcher Rebbe, Re'eh 5745 (1985)

This first of the signs of Moshiach enumerated by the Rambam is that he is "involved in Torah...like his ancestor Dovid". Moshiach will be flesh and blood, from the House of Dovid, and at first he will learn Torah like his father Dovid, like a batlanisher Yid [one who learns fulltime], like Dovid who learned Torah while he sent Yoav ben Truya, head of the army, to war. Through his involvement in learning Torah, in a way of "purifying a woman to her husband" (and not in order to make chiddushim, etc.)--he gives the power to Yoav to win the wars! And similarly, when a small girl lights Shabbos candles, this gives the power to the one who fights the wars of Hashem [ie, Moshiach] that he will be victorious."