How can we sure that such actions against the whole class of people will never happen again?

Find a copy of a bible story told in narrative form (for example, the good samaritan, any of the parables, old testament stories such as abraham and isaac, and so on). if you need finding one, ask your teacher. as you read the story, pick out the figures of speech. write each one down and identify it with the proper name. show the resulting list to your teacher.