According to Chassidic teaching, within each Jew is a spark of the Divine which cannot be extinguished. It is compared to the 'fire in the flint'. A glowing coal contains fire, but if it is put into water the fire is extinguished. A flintstone has the power to produce fire, and this power is not effected by the way the stone is treated. It can be immersed in water for a long time, and when it is removed it still has the power to produce a spark. The 'fire in the flint' is always present as a potential force.
In the same way, Judaism is always present as a potentially powerful force in the life of any Jew, however remote he or she may have become from Jewish life. The single flask of pure oil which was found in the Temple, and the Chanukah lights which it fuels, represent the eternal Jewish flame which might be hidden but cannot be put out. It is simply waiting for the opportunity to express its beautiful radiance.