And from the days of John the Baptist until now the kingdom of heaven suffereth violence, and the violent take it by force. (Matthew 11:12)

The tax gatherers and heathen, whom the scribes and Pharisees think have no right to the kingdom of the Messiah, filled with holy zeal and earnestness, seize at once on the proffered mercy of the gospel, and so take the kingdom as by force from those learned doctors who claimed for themselves the chiefest places in that kingdom. He that will take, get possession of, the kingdom of righteousness, peace, and spiritual joy must be in earnest. All hell will oppose him in every step he takes; and if a man be not absolutely determined to give up his sins and evil companions, and have his soul saved at all hazards, and at every expense, he will surely perish everlastingly. This requires a violent earnestness.

-Adam Clarke, Commentary on the Bible