There are only four mitzvot that involve the use of candles; Shabbos candles, the Havdalah candle, Chanukah candles and bedikat Chametz. What do all these have in common?
I think each of these mitzvot represents discernment, and differentiation. We light Shabbos candles to promote shalom bayis, domestic harmony. If it is dark and people repeatedly trip over one another or over unseen sharp objects, the mood in our homes can rapidly deteriorate. We bring light into our homes on Shabbos to differentiate between the pace of the week and the tranquility of Shabbos. As Shabbos ends, we light a candle once again, to differentiate between the sacred and profane. We invest considerable effort in preparing our house for Pesach, and then we light the candle to identify the previously undetected chametz. Rav Shimshon Pincus explained that the purpose of the Chanukah candles is found in their search for darkness. The menorah shows us what is dark, what we should avoid, what has no place in our lives – as individuals, as communities, and as a nation.
We live in a world in which there is plenty of darkness. Why do we need to search for more?! If the menorah is meant to search for darkness and represent discernment, we need to be honest and careful in who we choose as friends and allies – even, and especially, when so many are our enemies. Not everyone who is not our enemy is our friend, not everything that seems innocuous, sincere, positive or flattering can withstand further scrutiny, and some things that appear light are actually quite dark.