"Love your neighbour as yourself"
Love is central in Christianity. Within the Arima domain, the missionaries’ emphasis on this core aspect of the Christian Gospel made a profound impression on people
If you consult the Kōjien dictionary (a famous Japanese dictionary first published in 1955), you will be able to look up the word "gotaisetsu". It is defined as “an early Japanese Christian term meaning ‘love’”. Love is central in Christianity, and “gotaisetsu” was a word the missionaries used to try and succinctly express the Christian idea of love.
Back then, Japan was a country ravaged by many different wars and conflicts. Buddhism existed, but it was for feudal lords and people of high rank, and wasn’t something which most ordinary people could easily embrace. At the poorer end of society, people routinely killed and aborted babies in order to reduce the number of mouths to feed.
As a Jesuit catechism which was used in Japan (known as Dochirina Kirishitan) explained, the Christian idea of love had two dimensions: Firstly, love only the one true God whenever and whatever happens. Secondly, love your neighbour as yourself.
This emphasis on love was made known through the missionaries' actions. For instance, they established hospitals and orphanages. By saving the lives of children and of the sick, the missionaries were able to preach love not only through their words but also through their actions. In addition, they helped to establish small groups known as confraternities which performed various charitable works, and in the Arima domain (modern day Minami-Shimabara) a great number of these were formed. Later, around the time when Christianity had been banned and the Japanese church was going into hiding, such groups played an important role in helping Christians to continue their faith underground.