"And from the days of John the Baptist until now, the kingdom of heaven suffereth violence, and the violent bear it away"

Those are the words of Jesus in the Gospel of Saint Matthew (11th chapter)... and they are referenced in Pope Paul VI’s challenge to the Church to never stop evangelizing in ‘Evangelii Nuntiandi’ ('Proclaiming the Gospel,' 1975):

"This kingdom and this salvation, which are the key words of Jesus Christ's evangelization, are available to every human being as grace and mercy, and yet at the same time each individual must gain them by force – they belong to the violent, says the Lord, through toil and suffering, through a life lived according to the Gospel, through abnegation and the cross, through the spirit of the beatitudes. But above all each individual gains them through a total interior renewal which the Gospel calls metanoia; it is a radical conversion, a profound change of mind and heart."