Light and Truth contains lectures delivered by one with authority to teach and with one purpose in mind. That purpose is to teach gospel truth and to spread light, that all who receive might gain knowledge through the exercise of individual faith. Comprehension of the Doctrine of Christ is not based on command of a vocabulary or mastery of an argument. It is, instead, based on gathering light. Light is gathered by heed (obedience) and diligence alone. By following the light one has already received, one grows in light. This process leads to the “perfect day,” where the light has chased away all darkness. This is how men and women, like Christ, can grow from grace to grace, until they receive a fullness. By subordinating the will of the flesh to the will of the spirit, you gain light and truth. Do it to understand it. Once you understand, you will be able to tell when someone speaks with the power of the spirit, words of eternal life.