Mackey's Encyclopedia of Freemasonry defines the square as one of the most important and significant symbols of Freemasonry." Mackey further states "in Freemasonry, the square is a symbol of morality……. Everywhere however it inculcates the same lesson of morale any, of truthfulness, of honesty." We often hear it referred to as "the fourth part of a circle" meaning, literally, 1/4th of a circle.
I first learned about a square as a young child from my father who was a custom homebuilder and master carpenter. He always referred to this tool as a "Try Square.” He used this tool to mark lines on his work locating members of a house, mark lines to assure that all cuts were straight, square, and true, and always emphasized that a house would be stronger if all of the joints were properly cut and square to each other in all places. He never did explain his reason for referring to this tool as a "Try Square."
As I study Freemasonry and its deeper symbolic meanings, it becomes clear to me how this extremely useful tool for the Working Trades is given such a high place of honor in our Symbolic Trades to be referred to as "a Great Light."
When my father used his "Try Square," it was a standard of perfection by which he would test every single mark he made, every single cut he made, and tested every aspect of his work to make sure that every action met this standard. He was confident that by constantly testing every aspect of his work to this standard of perfection, his work would approach perfection and that every piece would fit together without difficulty or adjustment resulting in a strong and well constructed building.
In a similar manner, we are told that the "Square of Virtue" should be used as "a rule and guide in our life." If we make use of our "Square of Virtue" the way my father used his "Try Square," then we will be testing every decision we make, every action we pursue, and measure all aspects of our life against this standard of perfection. Just as my father was able to construct a strong, stable, and lasting home by ensuring that every aspect of this building was tested by his standard of perfection, we, too, can construct our moral buildings in a strong, stable, and lasting manner by ensuring that every action, thought, and decision are likewise tested by this standard of moral perfection, our own "Try Square" or "Square of Virtue."