How does Freemasonry define duty and virtue?

Duty is grounded in the candidate's obligation, a moral tie that binds a man in conscience and moral justice rather than civil law 1. This obligation creates specific duties categorized into affirmative points, which mandate certain actions, and negative points, which forbid others 1. Because this covenant is a solemn promise made to the fraternity, Masonic ethics demand complete sincerity without evasion, equivocation, or mental reservation, holding the promise binding in the direct sense it was intended to convey 1.

Virtue, inculcated from the first degree onward 3, is expressed through moral rectitude, charity, and truth 2. Newton summarizes the core moral code of the Craft through the scriptural rule to do justly, love mercy, and walk humbly 2. Within the lodge, virtue is treated as an active practice 3. A Mason is expected to preserve commendable conduct, judge with candour, admonish brethren with friendship, reprehend with justice, and provide relief to those in need while viewing a brother's interest as inseparable from his own 3.

The Craft also links virtue closely with intellectual discipline. The study of the liberal arts and sciences, particularly geometry, is presented as a means to refine human reason, reveal the order of the universe, and demonstrate moral truth 13.