Originally the Guardian understands this was adopted in America to enable young Bahá’í men to make certain arrangements in connection with their application for non-combatant status, upon their attaining the age of military service. There is really nothing about it in the Teachings or in the Administration. Your Assembly is free to do as it pleases in this matter.

Shoghi Effendi, Lights of Guidance, p. 154-155

In this day those who have fully recognized the station of Bahá’u’lláh, and are endowed with the gift of true understanding, have embraced His Faith not because they discovered that it would bring happiness to them, solve their personal problems, remove their afflictions and enrich their spiritual lives, but rather because they recognized that Bahá’u’lláh is the Manifestation of God for this age and were drawn to Him as iron is attracted to a magnet. Their eyes have been dazzled by the glory of His Revelation and their hearts seized by the potency of His Word. They know that the Cause He has revealed is exalted above all creation and that man has come into being primarily to serve it. This, and only this, should be the motive for following the Faith of God.

Adib Taherzadeh, The Revelation of Bahá’u’lláh v 2, p. 37