Discerning the Kingdom of God
Joseph on discerning where the kingdom of God may be found: "Where there is a prophet, a priest, or a righteous man unto whom God gives his oracles, there is the kingdom of God; and where the oracles are not, there the kingdom of God is not."1
Christ likewise identified a key: "Wheresoever the body is, thither will the eagles be gathered together."2 I believe the correct interpretation of this is that the eagles are the angels and the body is the body or followers of Christ.
John the Baptist was a single solitary man, yet because he had a connection with heaven, the kingdom resided with him, and not the religious hierarchy.
To most of the people who went about their merchandise and were busily engaged in life, the religious hierarchy were those who were authorized to interpret scripture with their learning and through whom they received valid temple ordinances. But a small group went into the wilderness to be baptized by John.
"John, at that time, was the only legal administrator in the affairs of the kingdom there was then on the earth, and holding the keys of power. The Jews had to obey his instructions or be damned, by their own law; and Christ Himself fulfilled all righteousness in becoming obedient to the law which he had given to Moses on the mount, and thereby magnified it and made it honorable, instead of destroying it. The son of Zacharias wrested the keys, the kingdom, the power, the glory from the Jews, by the holy anointing and decree of heaven." (HC, Volume 5, pg 257)
It didn't matter that many pretenders such as Bar-abbas (meaning "son of the father") had come before. It didn't matter that a religious hierarchy claimed to have keys. It was the responsibility of the people to discern that the kingdom rested with John. It was a test that most would fail.
1. HC, Volume 5, pg 257
2. Luke 17:37
Article: The Two Dispensations of Christ.