The two Shabbos (Sabbath) candles represent Zachor (Exodus ch.
20, remember the shabbos) and Shamor (Deuteronomy ch. 5, keep the
shabbos). All of the Yamim Tovim (festivals), Pessach (Passover)
included, are also termed "shabbos" and share in many of the
shabbos laws and observances, including lighting two candles
shortly before the holy day begins.