The first 10 letters of the Hebrew aleph bet are also the numerals one to ten. These act as symbols for the Ten Commandments. A Decalogue uses each letter to represent a number and a word, as well as each of the Ten Commandments in its entirety. Starting with Aleph (top right) they proceed alphabetically and numerically in order through Yud, the last letter on the bottom left.
 
Both Jewish and Christian tradition hold the Ten Commandments as laws given to Moses created by the Hand of G-d. As such, they come from the highest authority and are the foundation of our ethics and morality.