In the Bible, God appointed man to be stewards; He gave Adam the responsibility of tending the Garden of Eden (Gen. 2:15). After Adam's disobedience, man was given a conscience, and was responsible to live according to God's will; man failed miserably (Gen. 6:5). Following Noah's Flood, God established governments to oversee the nations of the earth, but none of them served God. So God created His own nation, one intended to set an example for the other nations (Gen. 12:2-3; Matt. 5:14). Of course Israel failed, and instead of being a "light to the Gentiles," they ended up becoming slaves to them (Ex. 1:8-11).
Four hundred years later, God raised up Moses, freed Israel, and gave them His Law. Not only did Israel fail to obey God's Law, they Crucified the only One who ever kept it (Acts 2:36; 2 Cor. 5:21; Heb. 4:15; 9:14; 1 Pet. 2:21-22; 1 Jn. 3:5). By rejecting their Messiah, Israel's stewardship over God's revelation was temporarily handed over to a group consisting of Jews and Gentiles who accepted His Son: the Church (Jn. 1:11-12; 3:16; Rom. 10:9-13; 11:25; etc.). Unfortunately, the Church, too, will fail to accomplish God's will "on earth as it is in heaven" (Matt. 6:10; 2 Thes. 2:3-12; 1 Tim. 4:1-2; 2 Tim. 3:1-9; 4:3-4; Rev. 2 - 3).
So, Jesus, Himself, will return to establish His 1000 year reign, and believe it or not, His efforts will also end in rebellion (Rev. 20:1-9)! In the end, there will have been seven stewardships of God's revealed will: Innocence (Adam); Conscience (Adam); Human Government (Noah); Israel (Abraham); the Law (Moses); the Church (the Holy Spirit); and the Millennium (Jesus). These stewardships are known as dispensations.
John Nelson Darby (1800-1882), is given credit for recognizing seven dispensations. Some criticize his paradigm as being artificially superimposed upon Scripture, but it is clear from the Word that revelation has been given to man a little at a time. For instance, the Church is called a mystery because it was not revealed in the Old Testament (Eph. 5:32). Daniel was told to "seal the book, even to the time of the end: many shall run to and fro, and knowledge shall be increased" (Dan. 12:4). Hebrews 1:1-2 says, "God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets, hath in these last days spoken unto us by [his] Son...." Man is only held accountable for what God has revealed to him.
Adam, Noah, Abraham, Moses, nor the Apostles had the New Testament.
We have it, and are accountable as stewards of its Truth - Jesus is Lord!