There is a strong sense of respect for the commanding officer. The soldiers eat, sleep, work and train together as one unit. When the time comes to fight, they have a common goal and support each other. Only then can they achieve their victory. The same is true of our spiritual lives.
Christians are all members of the same spiritual army.
We have a responsibility to our fellow brothers and sisters, to help and support them spiritually. Paul also compares the life of a Christian with that of an athlete. There are many characteristics of an athlete that can be instructive to Christians. For example, although there may be many runners in a race, only one can be the winner. Every sport has its own set of rules, and the athlete must abide by these regulations in competition.