When Jesus tells his disciples 'I have come to bring fire to the earth' he is not referring to an impending apocalypse but rather a spiritual fire, an enthusiasm ignited by the Holy Spirit to believe, live and spread the Gospel of salvation.
This Gospel passage occurs at the Last Supper shortly before Jesus' arrest and it reveals his awareness that the disciples will have difficulty in comprehending the significance of all that is about to transpire.
"Love is the light - and in the end, the only light - that can always illuminate a world grown dim and gives us the courage needed to keep living and working. Love is possible, and we are able to practice it because we are created in the image of God." Deus Caritas Est n.39