March 29. On this date in 1916, 'Abdu'l-Bahá wrote his "Tablet to the Bahá’ís of the Central States", which is the 3rd part of his "Tablets of the Divine Plan"

March 29. On this date in 1916, 'Abdu'l-Bahá wrote his Tablet to the Bahá’ís of the Central States, which is the 3rd part of his Tablets of the Divine Plan, outside the mansion of Bahjí, and addressed to the Bahá’ís of twelve Central States of the United States: Michigan, Wisconsin, Illinois, Indiana, Ohio, Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska and Kansas. Included in multiple books, the first five tablets were printed in America in Star of the West - Vol. VII, No. 10, September 8, 1916, and all the tablets again after World War I in Vol. IX, No. 14, November 23, 1918.

On December 23, 1918, 'Abdu'l-Bahá sent his secretary Ahmad Sohrab to the United States to personally deliver the Tablets of the Divine Plan. These collective letters, along with Bahá’u’lláh’s Tablet of Carmel and ‘Abdu’l-Bahá's Will and Testament were described by Shoghi Effendi as "three of the Charters" of the Bahá’í Faith, which along with the Kitáb-i-Aqdas (which Shoghi Effendi described as "the basic laws and ordinances on which the fabric of His future World Order must rest") set the foundation of the Administrative Order. Ahmad Sohrab would later be declared a Covenant-breaker by Shoghi Effendi.

O ye heavenly souls, O ye spiritual assemblies, O ye lordly meetings:
FOR some time past correspondence has been delayed, and this has been on account of the difficulty of mailing and receiving letters. But because at present a number of facilities are obtainable, therefore, I am engaged in writing you this brief epistle so that my heart and soul may obtain joy and fragrance through the remembrance of the friends. Continually this wanderer supplicates and entreats at the threshold of His Holiness the One and begs assistance, bounty and heavenly confirmations in behalf of the believers. You are always in my thoughts. You are not nor shall you ever be forgotten. I hope by the favor of His Holiness the Almighty that day by day you may add to your faith, assurance, firmness and steadfastness, and become instruments for the promotion of the holy fragrances.
Although in the states of Illinois, Wisconsin, Ohio, Michigan and Minnesota—praise be to God—believers are found who are associating with each other in the utmost firmness and steadfastness—day and night they have no other intention save the diffusion of the fragrances of God, they have no other hope except the promotion of the heavenly teachings, like the candles they are burning with the light of the love of God, and like thankful birds are singing songs, spirit-imparting, joy-creating, in the rose garden of the knowledge of God—yet in the states of Indiana, Iowa, Missouri, North Dakota, South Dakota, Nebraska and Kansas few of the believers exist. So far the summons of the Kingdom of God and the proclamation of the oneness of the world of humanity has not been made in these states systematically and enthusiastically. Blessed souls and detached teachers have not traveled through these parts repeatedly; therefore these states are still in a state of heedlessness. Through the efforts of the friends of God souls must be likewise enkindled in these states, with the fire of the love of God and attracted to the Kingdom of God, so that section may also become illumined and the soul imparting breeze of the rose garden of the Kingdom may perfume the nostrils of the inhabitants. Therefore, if it is possible, send to those parts teachers who are severed from all else save God, sanctified and pure. If these teachers be in the utmost state of attraction, in a short time great results will be forthcoming. The sons and daughters of the kingdom are like unto the real farmers. Through whichever state or country they pass they display self-sacrifice and sow divine seeds. From that seed harvests are produced. On this subject it is revealed in the glorious Gospel: When the pure seeds are scattered in the good ground heavenly blessing and benediction is obtained. 1 I hope that you may become assisted and confirmed, and never lose courage in the promotion of the divine teachings. Day by day may you add to your effort, exertion, and magnanimity.
Upon you be greeting and praise!

1. Cf. Matthew 13:23.