An interesting aspect of the presentation of friendship in this book is the way in which a bond of unity is established between the young soldiers in opposition to the older soldiers alongside which the younger soldiers fight. Consider the following quote and the way in which Paul describes the older soldiers and the way in which they betray the younger soldiers:
For us lads of eighteen they ought to have been mediators and guides to the world of maturity... to the future... in our hearts we trusted them. The idea of authority, which they represented, was associated in our minds with a greater insight and a more humane wisdom. But the first death we saw shattered this belief. We had to recognize that our generation was more to be trusted than theirs. ... The first bombardment showed us our mistake, and under it the world as they had taught it to us broke in pieces.
The theme of friendship is thus shown to be developed in the way that the younger soldiers are drawn together through their betrayal by the older generation as they persuade the younger soldiers to sacrifice their lives for patriotism and honour. Paul speaks of his disillusionment at the way in which those authority figures that should have been guides to the future were actually not at all. This older generation has no actual understanding of the realities of war, and therefore the younger generation are left to look to themselves and to each other to think about what their guiding principles must be in the face of this betrayal. Friendship then is something that is built on this disconnection between the generations, and a shared experience that the older generation has not been privy to.