For something to be "unleavened" means that it's been made without yeast. Since yeast is what makes bread rise and take on its airy texture, unleavened bread is relatively flat, dense and hard. The idea that unleavened bread is holy appears in both the Old and New Testaments and is still part of both Jewish and Christian traditions.

In the Word, bread represents the desire for what is good -- which gives us spiritual energy, just as bread gives us natural energy. Yeast, meanwhile, represents falsity -- so that bread made without yeast is a pure desire for good, free of falsity. This also makes sense because air represents our capacity to understand what's true -- which is the same capacity we use to embrace ideas that are false. Yeast causes bread to rise by producing gases as it ferments, thus adding "bad" air to the bread.

The Bible refers to the Lord in many different ways seemingly interchangeably. Understood in the internal sense, though, there are important differences. To some degree, the meanings all start with "Jehovah," which is the Lord's actual name. It represents the perfect, eternal, infinite love which is the Lord's actual essence. As such it also represents the good will that flows from the Lord to us and His desire for us to be good. "God," meanwhile, represents the wisdom of the Lord and the true knowledge and understanding He offers to us. The term "the Lord" is very close in meaning to "Jehovah," and in many cases is interchangeable (indeed, translators have a tendency to go back and forth). When the two are used together, though, "the Lord" refers to the power of the Lord's goodness, the force it brings, whereas "Jehovah" represents the goodness itself. In the New Testament, the name "Jehovah" is never used; the term "the Lord" replaces it completely. There are two reasons for that. First, the Jews of the day considered the name "Jehovah" too holy to speak or write. Second, they would not have been able to grasp the idea that the Lord -- who was among them in human form at the time -- was in fact Jehovah Himself. This does ultimately lead to a difference in the two terms by the end of the Bible. Thought of as "Jehovah," the Lord is the ultimate human form and has the potential for assuming a physical human body; thought of as "the Lord" He actually has that human body, rendered divine by the events of his physical life.