In the Babylonian Talmud in Masekhet Hullin 139b, a question is asked: What is the source in Torah for Esther? The answer given is V’anochi haster astir panai bayom hahul I will surely hide my face from you on that day (Devarim 31:18). Here in the world of ancient Persia, Anochi – that same I that took the Children of Israel out of the land of Egypt – with very public miracles – is hidden, concealed.
God is not mentioned in the Scroll of Esther. This is a world without direct prophecy, a world with no expectations of Divine miracles crashing in from the outside. This is, in fact, the familiar world in which we live. The real power of Purim is that we take on the role of making manifest the Divine Presence in a world where the face of Divine at times feels so hidden. We are to respond to the absence with our presence, and we do this through the four special mitzvot, the sacred obligations of Purim.