Ever since the Revival in 1717, for it is found in the earliest lectures, it was taught that Apprentices served their Masters with "Freedom, Fervency, and Zeal"j and the symbols of the first two of these virtues were Chalk and Charcoal. In the oldest instructions, earthen pan, which see, was designated as the symbol of Zeal; but this was changed to Clay probably by Preston, and so it still remains (see Fervency and Freedom).
The instruction to the Operative Mason to serve his Master with freedom, fervency, and zeal-to work for his interests willingly, ardently, and zealously is easily understood. Its application to Speculative Freemasonry, for the Master of the Work we substitute the Grand Architect of the Universe, and then our zeal, like our freedom and our fervency, is directed to a higher end. The zeal of a Speculative Freemason is shown by advancing the morality, and by promoting the happiness of his fellow-creatures.