During colonialization, Europeans frequently used Christian beliefs and principles to justify their actions. The most obvious way in which Christianity was used as justification is colonialization itself. Whilst, naturally, the gain of new land and new resources was the financial incentive of conquering other countries, Europeans often claimed that their main motivation was to bring an improvement of life to the native people of these countries, as they considered the native people underdeveloped and uncultured.
Given that the people in the “New World” were not Christians, Europeans took that as a sign of these people being uncivilized. Therefore, by conquering these countries, Europeans were able to spread the Christian faith and therefore were able to tell themselves that their conquest, despite all its cruelties, was actually a blessing in disguise. We can see this very clearly in the work of Kipling, for example, whose poem “The White Man’s Burden” illustrates this way of thinking.
Indigenous people were often seen as childlike, due to their lack of understanding of the Christian faith and therefore their perceived lack of cultural maturity. Therefore, Christian religion was used to justify the need to impose European lifestyle, values and customs onto these countries: it was seen as a way to help the native people become more civilized.
At the same time, the indigenous cultures and customs were severely restricted, often banned completely, especially if they were seen in clear contradiction to the Christian faith. This helped justify the strict and severe punishment of those indigenous people, who were often caught exercising their traditional beliefs instead of Christian faith.