April 21. On this date in 1939, Shoghi Effendi wrote "The passage in the Gospel of St. John 14:26, is a reference to the Revelation of Bahá'u'lláh, through Whose coming this prophecy was fulfilled."

April 21. On this date in 1939, Shoghi Effendi wrote (also here) "The passage in the Gospel of St. John 14:26, is a reference to the Revelation of Bahá'u'lláh, through Whose coming this prophecy was fulfilled."

1578. Reference in Gospel of St. John to Revelation of Bahá'u'lláh
"The passage in the Gospel of St. John 14:26, is a reference to the Revelation of Bahá'u'lláh, through Whose coming this prophecy was fulfilled."
(From a letter written on behalf of Shoghi Effendi to an individual believer, April 21, 1939)

also here

1657. Reference to Bahá'u'lláh in St. John
"The passage in the Gospel of St. John 14:26 is a reference to the Revelation of Bahá'u'lláh, through Whose coming this prophecy was fulfilled."
(From a letter written on behalf of the Guardian to an individual believer, April 21, 1939)