2 Maccabees 1:19

19 For when our fathers were being led captive to Persia, the pious priests of that time took some of the fire of the altar and secretly hid it in the hollow of a dry cistern, where they took such precautions that the place was unknown to any one.

The fire being talked about is the fire from the altar in Jerusalem. Whether the cistern was dry or wet, closed or open to the air, the fire would have gone out soon after being placed in. Now, a priest could not begin his work as a priest until he was thirty. In the Book of Numbers, priests were only counted from ages thirty to fifty (Num. 4:3; 4:23, 30, 35, etc., and cf. Ezekiel 1:1). So the "pious priests" during the beginning of the exile would have been, at the very least, one hundred years old when the captivity ended, and one hundred twenty on the high end.

Since it is unlikely that these men would have been looking for the fire, we can assume that some secret information was passed down as to where to find it. It is curious that not even a hint is given beyond "a dry cistern."

Although alchemists and others have been interested in this passage to identify what was meant by the secret fire, and whether it has something to do with the kundalini or serpentine fire, we must see that in the context of the book the point is that there was a miracle associated with the temple in Jerusalem as proof, over and above the law of Moses, that any other temple (i.e., the Hellenistic temple built in Alexabdria) was not legitimate.