...That which is the most important of all the affairs in this day is to teach the Cause of God!
SW.Star of the West, 25 vols. (1910-1935). Periodical issued each Bahá’í month. Vols. 1-12 reprinted 1978 in 8 volumes by George Ronald. Each issue Includes a section in Persian. https://bahai.works/Star_of_the_West