The theme of The Man of Law's Tale is constancy, a term nearly interchangeable in medieval times with patience. Constance (Custance) is the spiritual antithesis of the Wife of Bath, whose tale usually follows this one. Constance exemplifies endurance in adversity and trust in God. She also teaches constancy to total commitments and submission to law. Even though, in the beginning, she weeps for having been ordered to Syria, Constance does not strive against lawful authority represented by the wills of God, of parents, and of husband.
The emphasis in The Man of Law's Tale is the power and safety that comes with Christian constancy. In the medieval sense, Christian constancy meant a steadfast devotion to God and an indifference to the world. The poem opens with a contrast between the wealth of this world — characterized by the wealthy Syrian merchants and the Sultan — and the wealth of the spirit, summed up in the character of Constance. She is the perfect and the universal. She is portrayed in poverty and in prosperity, in joy and sorrow, in defeat and in victory. Looking forward to the bliss of the next world, Christian Constance can tolerate many ills, including grief, abandonment, and the cruelty of Fortune. Constance can resist the temptations of this world knowing that she will be rewarded in the next world.
