Initially, the Oracle was intended to be a guide for the people of Yonada, which would advise the leadership on Yonada on how best to run the world-ship as it made its way towards Lorina. Over the centuries, the people began to ignore the advice of the Oracle, which resulted in severe environmental problems on Yonada. This resulted in a number of violent upheavals, the last of which brought a fundamentalist regime to power. Afterwards, the Oracle was reprogrammed with this new fundamentalist ideology. The Oracle then enforced its will through the use of the "Instrument of Obedience" which could control the thoughts and actions of the inhabitants. (TOS novel: Ex Machina) During the course of Yonada's voyage, the computer had malfunctioned and diverted the worldship's course from entering into orbit over Daran IV to a collision course with Daran V.
In 2268, Captain James T. Kirk, Commander Spock and Dr. Leonard McCoy successfully disabled the Oracle and corrected the worldship's course to Daran IV. (TOS episode: "For the World is Hollow and I Have Touched the Sky")
Following the establishment of the Lorina colony in 2270, many citizens wanted to restore the Oracle's control over their lives as the early days of establishing the colony had been hard. In 2273, a small group of extremists led by Dovraku succeeding in boarding Yonada - hiding amongst a delegation of religious Lorini assembling on the ship for peace talks. Dovraku was able to reprogram and reactivate the Oracle. After having the Oracle kill Minster of Security Tasari, Dovraku threatened to kill other hostages unless Spock agreed to enter into a mind meld with him and the Oracle in order to bring about an ascension similar to that of the Voyager.
Dovraku was then able to launch all the remaining defensive missiles towards Lorina and used Spock's knowledge of the Enterprise to shut down the shields and tried to reprogram the transporter to facilitate the ascension. While struggling to keep Dovraku from carrying out his plans, Spock discovered the painful childhood memories that had traumatized Dovraku, and were driving him to commit his insane acts. Forcing Dovraku to face his memories left the Lorini male in a catatonic state. With Dovraku's influence gone Spock was able to override the Oracle, shut down all the missles, and, using the Oracle's voice, force the Lorini rebels to surrender.
The meld with the Oracle also helped Spock to locate a hidden data archive that had been hidden to prevent its destruction during the uprisings that had taken place during Yonada's journey to Lorina. This archive had data going all the way back to the construction and launch of the generational ship, including the original intent of the builders for the Oracle to bring all the Fabrini together and pass down the knowledge of the Fabrini through the generations of people who would live on the world-ship. The governmental and religious leaders of the Lorini left the peace talks feeling that perhaps the Oracle could once again serve as a bridge to help bring their race together. (TOS novel: Ex Machina)