Selfless Commitment

This is what the British Army has to say about it:

"On joining the Army soldiers accept an open-ended commitment to serve whenever and wherever they are needed, whatever the difficulties or dangers may be. This commitment is reflected in the wording of the Loyal Oath which is taken on attestation, and in which soldiers agree to subordinate their own interests to those of the unit, Army and Nation, as represented by the Crown. This could involve participation in a wide range of operations, from warfighting through peace support operations to assistance to the civil authority. Such commitment imposes certain limitations on individual freedom, and requires a degree of self-sacrifice. This may involve, for example, long periods of separation from family and friends, the disruption caused by a move at short notice, and the carrying out of regimental guards and duties. Ultimately it may require soldiers to lay down their lives. For those in positions of authority, it also requires them to discharge in full their responsibilities and their duty of care to subordinates, whether in peacetime or on operations.

This two-way obligation forms a covenant between the Army and its soldiers. Both share a common bond of identity, loyalty and responsibility for each other which is unwritten but unbreakable, and which has sustained the Army throughout its history. Soldiers volunteering for the British Army accept that, by putting the needs of the Service before their own, they will forgo some of the rights enjoyed by those outside the Armed Forces. But in return they can at all times expect fair treatment, to be valued and respected as an individual, and to be rewarded by reasonable terms and conditions of service. By extension, this covenant also exists between the Army and the Nation it serves."

Values & Standards - A Commander's Guide.