He was beautiful and had tabrets and pipes built into his body. Thou wast perfect in thy ways from the day that thou wast created, till iniquity was found in thee. Now, he leads many people away from God using his knowledge of music. Each of these are important to complete a good musical piece. Melody is meant to carry the message.
Harmony brings about a unity in the body of the musical piece at various points.
The beat is to keep the timing and also is used for accent. However, in rock and rap music, things are different. The beat is used to drown out the other factors and drive home the message. It is like someone taking their finger and poking you in the chest repeatedly to force you to receive their message. As Satan desires to control the lives of people, the beat is used to force one to receive the message.