How does the triangle relate to the concept of the Divine in Masonic teachings?

The triangle serves as an emblem of Deity, representing the Eternal, All-Powerful, and Self-Existent 1. Because it is the simplest closed geometric figure—having no loose ends, beginning, or ending—it early became a primary symbol for God, who is likewise conceived as first, uncreated, and without beginning or end 3.

When drawn with rays emanating from its center, the radiated triangle signifies Divine Light, symbolizing the Eternal Light of Wisdom that surrounds the Supreme Architect and radiates throughout creation 1. As the Greek letter Delta, the triangle also relates to the Pythagorean tetractys, a triangular arrangement of ten points that symbolized the Creator and the generated universe 1.

Within the symbolic structure of the lodge, the triangle represents active divine force in contrast to the square, which typifies passive matter and humanity 1. W. L. Wilmshurst expands on this dualism, viewing the compasses and square as approximations of an upward-pointing "Fire Triangle" of active spirit and a downward-pointing "Water Triangle" of the passive soul, both rooted in the Divine Word 2.

The triangular form is further expressed in the arrangement of the three Lesser Lights 3. While specialized forms such as the triple triangle are used in Christian or high-degree rites to denote specific doctrines like the Trinity, within the Craft degrees the triangle remains a general emblem of Deity and divine illumination 131.