There is sort of a cadre of Christian brothers who I've been doing jail and prison ministry with. You become very close to people when you do God's work together. Whether is carpentry, or evangelism, if you're doing God's work, there is a special blessing in doing it with other Christian men.
I beleive that God is pleased when we serve Him and He blesses us. He must be even more pleased when we work in harmony with other Christians. And I think he blesses us all the more when we're working in this way. Not only in the friendships (although that is a great blessing) but also there is something special about being about God's work with Christian brothers.