Imagine that someone gives you a million dollars to invest. You're pretty smart and make a few good investments, and very soon, the million is worth ten million.

Obviously you have to give the original million dollars back to your benefactor, but you do get to keep the other nine million.

It's the same way with the festivals: Hashem gave us Pesach, Shavuot and Succot as gifts - we didn't deserve them - they are a free hand-out - a million dollar gift. However, Chanukah and Purim were earned by the Jewish People.

The Jewish People earned Chanukah because they were prepared to give up their lives in battle to preserve the purity of the Torah. Purim was the reward for the voluntary acceptance of the Oral Law in the time of Mordechai and Esther.

There's an interesting parallel here: The 'weapons' that Israel employed to fight the threat of physical genocide at the time of Purim were spiritual - fasting, prayer and repentance. Whereas, at the time of Chanukah, the threat to Israel was spiritual genocide - the Greeks wanted to uproot the faith of Israel, to darken the eyes of the Jewish People by removing the light of Torah. What was the response to this spiritual assault? Physical warfare.

It's as though we say to Hashem "Your light is in our hands, and our light is Your hands."

When we guard Hashem's light - the light of Torah - by showing that we are prepared to give the light of our lives for it, as was the case during the Maccabean war of Chanukah, Hashem guards the light of our lives.

Similarly, when our enemies seek to extinguish the light of our lives, as at the time of Purim, our salvation comes by way of guarding Hashem's light - Torah and mitzvot - and thus Hashem turns to our petition and guards the light of our lives. "Your light is in our hands, and our light is Your hands."

Source: Rabbi Eliyahu Kitov