Thomas Hobbes said, "Life is nasty, brutish, and short." When we're born, this is what we're up against. So early on we begin the quest to minimize pain and maximize pleasure. And we gather around ourselves a nest of things which aid us in our nest quest: cars, houses, credit cards, service contracts, clubs, toys and the like. To support our quest, we make commitments: mortgages, jobs, insurance policies and so forth.

So when Jesus comes along and says things about nests it gives a would-be disciple pause:

"Foxes have holes and birds of the air have nests, but the Son of Man has no place to lay His head." (Luke 9-58).

He went on from there and said some other things on the same theme:

"Let the dead bury their dead, but you go and proclaim the kingdom." (Luke 9:60)

"A man's life does not consist in the abundance of his possessions." (Luke 12:15)

"Do not worry about your life, what you will eat; or your body, what you will wear." (Luke 12:22)

"Sell your possessions and give to the poor." (Luke 12:32)

"Any of you who does not give up everything he has cannot be my disciple." (Luke 14:33)

"No servant can serve two masters. You cannot serve God and money." (Luke 15:13)

The reason it's so hard to disciple adults is that we adults have got so much to abandon. Our comfort zones are so big. We want to serve two masters and we're caught in a no-man's land wanting to take care of just a few more obligations before we can radically follow our Master. It's no coincidence Jesus called out mostly young people. Just look at how comfortable you've made your own nest. How difficult would it be to leave it?