Tosefta sobre Isaías 43:7

Those of the House of Garmu were highly skilled in making the showbread, and they did not want to impart their knowledge [to others]. The Sages sent forth and brought experts from Alexandria, which is in Egypt, that would bake just like them, but they were not experts in removing [the showbread from the oven]. Those of the House of Garmu would light the oven from the outside and would remove [the showbread] from the inside. Those of Alexandria were not able to do so, and there are those who say that it got moldy. And once the Sages learned of the matter, they said, "The Place only created the world for His own glory," as it is said (Is. 43:7), "All who are call out with My Name [etc.]." [The Sages] sent for them, but they did not come until they doubled their salary. They had given them twelve maneh every day, and when they came back they gave them twenty-four maneh every day -- the words of Rabbi Meir. Rabbi Yehuda says, twenty-four [maneh] they would give them every day, and when they came back they gave them forty-eight maneh. The Sages said to them, "What did you see that you did not want to impart your knowledge." They said, "It was known to the house of our fathers that in the future the Holy Temple would be destroyed, and we did not want to teach [others] so that it would not be made before [objects of] idolatry in the same way that it is made before the Place." And on this matter their name is remembered for praise, that [ritually] clean bread is never found in the hands of their sons, or in the hands of their daughters, so that it is not said of them, that they satiate themselves with showbread, to fulfill that which is said (Num. 32:22), "And they shall be clean before the Lord."