In each of the first four dispensations, God spoke directly to man. He spoke to Adam at the beginning of the first two, and He spoke to Noah and Abraham to begin the next two. The fifth dispensation is no different in its beginning: God spoke to Moses (Exodus 3:4). As far as anyone knows for sure, up until this point in man's history, there was no written record. This definitely changed with Moses. God inspired him to write the first five books of the Bible, known as the Pentateuch or the Torah. Another name for these books is The Law. The first four dispensations are all found in Genesis. The fifth will involve the rest of the Old Testament and parts of the New Testament. It covers a period of time that is at least 3,500 years long (there is a parenthetical period of two thousand years, the sixth dispensation, within the fifth).
There are several significant changes during the dispensation known as The Law. There are 613 laws that cover everyday living, worship, and sacrifices. There are seven holy days called the Feasts of Israel, all of which are a pictures of events involving the Messiah. It is The Law that solidifies Israel as a unique nation. In addition to circumcision, Israel had special dietary laws and recognized the sacredness of the Sabbath. Included in the fifth dispensation are books of the Bible known as The Prophets, and The Writings, or in other words, the rest of the Old Testament. Within the thirty-nine books, there is one central theme: The coming of the Messiah. The Hebrew people were constantly being subjugated by world empires (Assyria, Egypt, Babylon, Medo-Persia, Greece, and Rome). They longed for the day when their King would conquer the world and rule forever. They would have a long wait.
Another major factor that makes the fifth dispensation unique from all others, is that it is divided into two parts: the years that lead up to the arrival of their Messiah, and a short period known as the Tribulation. This seven year period, also know as the Tribulation, the time of Jacob's Trouble, and Daniel's Seventieth Week, serves as God's judgment for this dispensation. In between the two is a period that was a mystery to Israel (Romans 11:25; 16:25; Colossians 2:2; etc.), known as The Church. What Israel could not see was that the Messiah would come twice. He came as the Lamb of God to fulfill the picture of the The feasts of the Passover, Unleavened Bread, and First Fruits. He will return as the Lion of the Tribe of Judah to fulfill the picture of the feast of Trumpets, Atonement, and Tabernacles. I will cover this in the sixth dispensation.
The Dispensation of the Law might be described as:
Stewardship: Israel to govern by the Law (numerous passages)
Foods: Kosher foods only (numerous passages)
Command: Obey the Law or sacrifice when failing to do so (numerous passages)
Response: Disobeyed God in both the spirit and letter of the Law (numerous passages)
Judgment: The Tribulation (Daniel 24-27; Jeremiah 30:7; etc.)