How does it happen? A path all to often followed over an extended period of time might look something like this.
The nefarious process begins with a subtle loss of desire for holiness, then an equally slight emphasis on something else that is spiritual, which seems to balance the scales from the injustice of selectively ignoring sections of the Word of God. In time, this is followed by faintly and implicitly equating holiness with extremism or legalism, and moderate libertarianism with grace; then comes the openly disparaging remarks concerning church discipline. Eventually the world’s wisdom and ways of selfishness and relativism are no longer resisted, but rather they are welcomed, and the world eventually lays her death grip on every aspect of the church.
By this time, the church no longer wants to be radically different from the world because she sees this as a threat to the lost receiving the church and her message, or possibly thinks the lost would view the church as anachronistic the cardinal sin to the church of modernity and postmodernity. The result is that the church becomes half-church and half-world, for which neither God nor the world has much use. Tragically, the church is the last to understand this final fate awaiting all churches that dine at the table of the kosmos world. This is all done of course by basting the delectables of the world with sanctified Christian clichés until they appear scrumptious, but the end is the same as the world’s, only with greater deception.
“But like the Holy One who called you, be holy yourselves also in all your behavior; because it is written, You shall be holy, for I am holy” (1 Peter 1:15-16).