The nineteenth path is one of the horizontal paths, joining Chesed, Mercy, to Geburah, Severity, across the Tree and linking the two great opposed powers of expansion and restraint whose balance the Tree depends on. It carries the letter Teth, whose name means "serpent", the coiled snake, an image of hidden strength, of the life-force and of the wisdom and danger the serpent has signified across traditions.
In the Sefer Yetzirah Teth is one of the twelve simple letters assigned to the twelve zodiac signs, and it is given to Leo, the lion, the fixed fire sign of courage, vitality, sovereignty and the sun's strength. The attribution of the letter to Leo belongs to the ancient Jewish scheme in which the twelve single letters correspond to the signs and the months; the lion's strength and the serpent's coiled power together suit a path that binds mercy and severity, the taming of force by wisdom across the central axis of the Tree.