Lechem Mishneh: The Luchot
One should have two Challot, which hint to the two Luchot. (Zohar, R”M, Eikev 273a) The Luchot were given on Shabbat (Shabbat 86b), and we recreate the gift when we have Lechem Mishneh.
The Zohar uses the word “Zugot,” which means pairs. The Mikdash Melech explains in the name of the RMaZ that this is because Rabbi Shimon bar Yochai teaches (Yerushalmi, Shekalim 6:1) that the Ten Statements were written ten times on each of the two tablets. This is why we hold the bread with all ten fingers.
In another place, (R”M, Pinchas, 245a) the Zohar teaches that we should have four loaves. In the Tikkunim (#47 84a) it is suggested that we have 12 loaves. Even those who use twelve loaves, hold only two Challot in their ten fingers when reciting the blessing.