In Old Craft iconography, the Old Master is sometimes depicted as a horned (or antlered) skull with a flame between its horns. He is thus the Flammifer, the líht-bera, the Lucifer.
The image takes its origin from Continental trials; French witches frequently deposed that the Devil appeared at the sabbat in the form of a He-Goat with a candle burning between his horns. This is how Jeanne Bosdeau saw him at the Puy de Dôme in 1594. The witches would then light their own tapers or torches (as we still do) from the god's fire: the Lord of the Sabbat giving illumination to his people.
The witch-fire is the power of life that burns in each of us. It is said to be threefold: the fire in the head, the fire in the heart, and the fire in the loins.