Although we will not be able to fully understand the mystery of sacrifice in this world, we can find through the Writings that there is a tremendous power released when man sacrifices something in the path of God. …In one of His Tablets, 'Abdu'l-Bahá explains that not until a seed completely disintegrates under the soil can it produce a tree. It is then that an object as insignificant as a seed, by sacrificing itself completely, will be transformed into a mighty tree with branches, fruits and flowers. It is the same when man sacrifices something of his own.
A human being has two opposite forces working within him, the animal and the spiritual. The animal nature inclines man to the material world. The Manifestations of God have exhorted their followers to detach themselves from material inclinations so that their spiritual side may dominate over the physical. As we have already stated [previously] … by detachment is not meant renunciation of the world, mendicancy or asceticism. In a nutshell, detachment is to submit one's will to the will of God and to seek His good pleasure above one's own. Therefore, the challenge to every believer in this life is detachment from all else save God. To become detached from something of this world is often a painful process and this is where sacrifice becomes necessary, because man is attracted to the material world and to his own self by nature. When the believer sacrifices something of this world, an act which entails pain and suffering or deprivation of material benefits, he will attain to a higher spiritual status, depending on the measure of sacrifice.
And when he gives up something dear to him for the sake of the Cause of God, as testified by Bahá'u'lláh in His writings mysterious forces will be released which will enable the Faith to grow. To offer up one's time, to labour for the establishment of the Faith in a locality, to give up the comforts of home and to go as a Bahá'í pioneer to foreign lands, to offer up one's substance for the promotion of the Cause, to be persecuted for one's faith, all these sacrifices are meritorious in the sight of God and will undoubtedly bring victory to the Cause of Bahá'u'lláh, provided one's motives are pure and sincere. But to lay down one's life in the path of God when circumstances demand it is the ultimate in the realm of sacrifice. It is like a seed which sacrifices its all to the soil. Thousands of martyrs in Persia, faced with the challenge of either relinquishing their Faith or dying, have released enormous spiritual forces for the promotion and consolidation of the Cause of Bahá'u'lláh by their sacrifice. For two things are primarily responsible for the spreading of the Faith and its penetration into the hearts of men. One is the outpouring of the world-vivifying, soul-stirring energies of the Revelation of Bahá'u'lláh which like the rays of the sun in spring give new life to all created things, the other is the blood of the martyr which waters the tree of His Cause. In one of his letters to the believers of the East, Shoghi Effendi has attributed all the great victories of the Cause in the western world, including the conversion to the Faith of Queen Marie of Rumania, to the mysterious forces released by the blood of countless martyrs in Persia. However, in this Dispensation Bahá'u'lláh has exhorted His followers not to seek martyrdom. He has instead decreed that the believers should live to teach the Faith, and has exalted the reward of teaching to that of martyrdom. (Adib Taherzadeh, The Revelation of Baha'u'llah v 3, pp. 212-213)