Since 1884, many western Protestant missionaries came to Korea. The missionaries initially treated of the spiritual perspective of Koreans as superstitious and ignorance-oriented. Especially in the field of medicine, the Western perspective seemed to be far advanced than the Korean traditional perspective. According to the Korean traditional view, sicknesses was in many cases caused by intrusions of spiritual beings. Therefore, to cure the sick, one had to cast out those spiritual beings out of the bodies through placations or by force. With such perceptions, Korean people were not able to overcome the hard situations caused by the contagious diseases such as pestilence, small pox, and typoid fever. Western missionaries could take advantage on those matters in order to help Koreans and thereby achieving the trust of Korean government. Even though Western science and medicine proved their effectiveness through such medical works, excessive reliance can cause one to fall into the idolatry of worshipping medicine instead of God. Throughout the development in the area of science and technology, Westerners have tended to look everything through the scientific perspectives. Through such trends Western societies were believed to run the course of secularization throughout the 19th and 20th centuries. God and His supernatural world have been marginalized especially in public areas. According to Professor Paul G. Hiebert, even missionaries with severe Western cultural backgrounds have difficulties in understanding the spirit world of the native people. Early missionaries to Korea were not exceptions. They also had difficulties when they first met the Koreans and tried to understand their spiritual view points. In contrast to the Westerners who generally do not recognize the spiritual beings around them, the Koreans recognized the spiritual beings such as ghosts, ancestors in almost every aspect of their lives. Koreans were famous in maintaining the practices related to such spiritual beings throughout their ancient history. When the missionaries first observed practices related to the spiritual beings, they judged Koreans to be ingnorant or superstitious. However, the missionaries continuously tried to understand the people and their worldviews. When they were unable to understand the Korean worldview on the spiritual beings, they resorted not to the Western naturalistic perspective but to the Bible. Through comparison between the Korean traditional perspectives and the Biblical perspectives, they discovered that the Biblical perspectives were more similar to the Korean traditional perspectives. And with careful observation and examination of the Korean ministers’ deliverance works, they changed their thought about the spirit world. The demons and spiritual beings which were regarded to harass Korean people were not supterstitions or fatacies. They were real beings confirmed by the Bible. The native Korean ministers contributed a lot in the paradigm shift from Western perspective to the Korean perspective on the reality of spiritual beings. The Korean ministers viewed the Bible differently. They believed Bible stories where the possessed were released by Jesus and his disciples. The faith of Korean ministers proved to be simple and firm enough to follow the practices of Jesus and his disciples in casting out demons. When the missionaries heard about the stories of deliverances by the Korean ministers and believers, they did not stop but rather carefully examined such behaviors in light of the Bible. The final criteria of missionaries were not the western but the Biblical perspective. With such criteria, they accepted and recognized the deliverance ministries of the Korean believers. Some missionaries, when asked if they could cast out demons out of troubled, succeeded in the deliverance ministries. In my estimation, the Nevius mission plan contributed greatly in making harmony and cooperation between the missionaries and the Korean ministers. God brought Koreans who were troubled with spiritual bondage into the Kingdom of God through such faithful servants of God. The reasons the early protestant missionaries to Korea brought such great success in evangelizing Korea were foremost their deep reliance to the Bible as the Word of God and secondly their deep understanding of Koreans and their ways of thinking.