I've started reading through Life Together, so I'll try and post some ruminations and/or quotes as I meander through it.
Bonhoeffer notes that the Christian life is lived among enemies. The Christian, "belongs not in the seclusion of a cloistered life but in the thick of foes. There is his commission, his work." (17). Christians are scattered people, dispersed to be, "the seed of the kingdom of God in all the world." (18). Moreover, many believers are unable to fellowship with brothers and sisters because of imprisonment, exile, sickness, etc. Thus Christians should be profoundly grateful for whatever community they have. In Bonhoeffer's words,
...let him who until now has had the privilege of living in a common life with other Christians praise God's grace from the bottom of his heart. Let him thank God on his knees and declare: It is grace, nothing but grace, that we are allowed to live in community with Christian brethren.(20)