God grants our prayers through His universal Manifestations

O handmaid of God! Prayers are granted through the universal Manifestations of God. Nevertheless, where the wish is to obtain material things, even where the heedless are concerned, if they supplicate, humbly imploring God's help- even their prayer hath an effect. (‘Abdu’l-Baha, ‘Selections from the Writings of 'Abdu'l-Bahá’; The Compilation of Compilations, Vol. II, The Importance of Prayer, Meditation and the Devotional Attitude)

Means through which “union and harmony among nations” will be achieved

...every great Cause in this world of existence findeth visible expression through three means: first, intention; second, confirmation; third, action. Today on this earth there are many souls who are promoters of peace and reconciliation and are longing for the realization of the oneness and unity of the world of humanity; but this intention needeth a dynamic power, so that it may become manifest in the world of being. In this day the divine instructions and lordly exhortations promulgate this most great aim, and the confirmations of the Kingdom also support and aid the realization of this intention. Therefore, although the combined forces and thoughts of the nations of the world cannot by themselves achieve this exalted purpose, the power of the Word of God penetrateth all things and the assistance of the divine Kingdom is continuous. Erelong it will become evident and clear that the ensign of the Most Great Peace is the teachings of Bahá'u'lláh, and the tent of union and harmony among nations is the Tabernacle of the divine Kingdom, for therein the intention, the power and the action, all three, are brought together. The realization of everything in the world of being dependeth upon these three elements. (‘Abdu’l-Baha, The Compilation of Compilations, vol. II, Peace)