"The missional part was Jesus leaving his Father's side in the heavens and coming to us in the form of a human. The incarnational part was how he took on the flesh and lived with us. Said another way, missional sentness is focused on leaving and everything related to going, but incarnational represents how we go and what we do as we go.... Words communicate what we know; posture represents what we believe and feel. Therefore, posture is the most important part of relationship and communication. Posture shows true emotion and the intent of our heart. When we try to figure out why those outside the church aren't interested in our 'good news,' it may have nothing to do with our message, but with our nonverbals.... Posture is about helping people want to hear the truth." p. 38-39
The book goes on to talk about the posture - the attitude and habits - that we need to demonstrate as we move about in the world and seek to represent Christ in a way that draws people to him.
From my experience, there are several causes of "bad posture" among Christians. One is lives that don't demonstrate a difference because of the presence of Christ. Our lives are too much like the world's in our values and lifestyle or they can be the negative and condemning. Another cause of "bad posture" can also be our habit of slowly withdrawing from the world and those who don't share our values. We slowly remove meaningful relationships with those outside of faith. I love this sentence:
"Influence doesn't happen by extracting ourselves from the world for the sake of our values, but by bringing our values into the culture." p. 31
If you're a church leader, read The Tangible Kingdom. If you're a church planter, read The Tangible Kingdom. If you're a Christian hungering to be a part of God's mission in our world, read The Tangible Kingdom.