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)