There are 22 letters and they are symbolic as well as having a mathematical value. A stands for the head of an ox. B represents a tent or dwelling, C represents a camel & includes commerce, D represents a door and so on. Simple enough a child can understand yet so advanced the most advanced people can not fully grasp the meaning. If you begin with B as a tent, today people live in high rise apartment, also a tent includes the tabernacle. When they entered the promised land their dwelling went from a simple tent to a permanent building with wood, brick and mortar. This is also the incarnation and God's desire to dwell with man. Going from simple to complex like this is pretty easy to be accurate and stay on track. When Jesus says He is the door or the gate this is all represented by one simple letter in the Hebrew. When we have a gateway to a city we have judges that determine what can enter in or what can leave the city.