And from the days of John the Baptist until now the kingdom of heaven suffereth violence, and the violent take it by force.
Note 2 at Mt 11:12: The phrase "suffereth violence" in this verse is translated from the Greek word "BIAZO," and it means "to force, i.e. (reflexively) to crowd oneself (into), or (passively) to be seized" (Strong's Concordance). The same Greek word was used in Lu 16:16 and was translated "presseth" there.
The idea that Jesus was communicating in both of these passages was that before the time of John the Baptist, the only way to approach unto God was through the Old Testament laws and sacrifices. In Jesus' time, these had become cold and cumbersome rituals in which the heart of the people was far from God (Mt 15:3-9). When John the Baptist came in the power of the Spirit (2Co 3:6), preaching a turning away from sin (Mt 3:8) and faith in the coming Messiah (Mt 3:11), multitudes, who previously were not actively seeking God, began flocking to the wilderness to be baptized by John, confessing their sins and putting their faith in the coming Messiah. They were truly "pressing in" to the kingdom of heaven, overcoming any obstacle or opposition posed by laws, traditions, unbelief, or any power Satan threw at them, in order to receive the message that John preached. They were "violently resolved" in their zeal and forcefully pressing in to the kingdom of heaven.
Today, as in the days of John the Baptist, Satan is opposing the preaching of the Gospel, and only those who are violently resolved to receive God's best will have it (Jas 4:7).