...the Christian, too, belongs not in the seclusion of a cloistered life, but in the thick of foes. There is commission in his work. (p.17)Exactly. We are commissioned to go out into the world (Matthew 28:19-20). I don't know that I would use the word foes to describe the relationships with others, but the sentiment is one I resonate with - We leave the comfort and safety of our Christian bubbles to engage the world around us.
Christianity means community through Jesus Christ and in Jesus Christ. No Christian community is more or less than this...We belong to one another only through and in Jesus Christ. (p. 21)While we are called to go out into the world, we are also called to be in fellowship together, whether for a few minutes, an hour, whatever. In that time we find encouragement. For the goal of Christian community (according to Bonhoeffer) is to meet one another as bringers of the message of salvation. It is Jesus that we see or seek in others and that others see and seek in us when we gather.
...the Christian is the man who no longer seeks his salvation, his deliverance, his justification in himself, but in Jesus Christ alone. (p. 21-22)I find in Bonhoeffer a great relenquishement of self. In that the focus is no longer on self, but in the "Word of God in Jesus Christ." For instance, conviction or righteousness comes from Jesus - through the word of God. It meets us where we are. And when others see us, it is Jesus they see and seek.
In a sense this is a loss of self, however maybe a better way to say it is that it is a way of seeing ourselves as "right-sized." We see self in a divine perspective - we are vessels or jars of clay through which to carry the message of salvation (the one we are reminded of by our brothers and sisters in Christ) and empty it out into a world that is thirsting for such a message.