In the Hebrew Testament fire symbolizes the word of God pronounced by the prophet. But it also signifies the divine judgement that purifies his people by passing in their midst.
We can say the same about the word of Jesus: it builds up, but at the same time it destroys all that has no consistency, all that needs to come down, all that is vanity, and it leaves only the truth standing.
John the Baptist had said of him: “He will baptize you with the Holy Spirit and fire” (Lk 3:16), pre-announcing the Christian baptism inaugurated on the day of Pentecost with the outpouring of the Holy Spirit and the appearance of the tongues of fire (See Acts 2:3).
This then is Jesus' mission: to cast fire on earth, to bring the Holy Spirit with his renovating and purifying force.

«I have come to set the earth on fire, and how I wish it were already blazing!»

Jesus gives us the Spirit. But how does the Holy Spirit act?
He fills us with love and he wants us to keep this love enkindled in our hearts.
What kind of love is it?
It's not an earthly, limited kind of love. It's the love that the Gospel speaks of. It's a universal love, like that of the heavenly Father who makes the sun rise and the rain fall on the good and the bad, including enemies (See Mt 5:45).
It's a love that doesn't wait for the others to take the first step, but which always takes the initiative by loving first.
It's a love that makes itself one with every person: suffering and rejoicing with them, sharing their worries and hopes. And when needed, it does so in a concrete way, with deeds. So it's not simply a sentimental love that is expressed with words alone.
It's a love directed to Christ in our neighbor, mindful of his words: “You did it for me” (Mt 25:40).
It's a love that leads to reciprocity, to loving one another.
Because this love is a visible, concrete expression of our life based on the Gospel, it underlines and testifies to the word that we can and must offer in order to evangelize.

«I have come to set the earth on fire, and how I wish it were already blazing!»

Love is like fire – what is important is to keep it lit, and so it must always burn something. First of all, it must consume our selfishness, and it does this because by loving, we are projected outside of ourselves: either towards God, by carrying out his will, or towards our neighbors, by helping them.
Even a small fire, if it is fed, can become a large blaze – that blaze of love, peace, and universal brotherhood which Jesus brought on earth.

Chiara Lubich