August 23

…among the members of the Bahá’í community the celebrations of former religious dispensations should be abandoned. However, Bahá’ís are encouraged to "consort with the followers of all religions in a spirit of friendliness and fellowship," and there is no harm in Bahá’ís sharing Christmas with Christian relatives or friends. Indeed, families may contain both Bahá’ís and non-Bahá’ís, and the participation by Bahá’ís at celebrations of Christmas or of other religious observances, should not be made into a source of conflict but rather be used as an opportunity for demonstrating the honor due to other religions and also as an incentive for developing the celebration of Bahá’í Holy Days and anniversaries. 
- The Universal House of Justice  (From a letter dated 6 November 1986 written on behalf of the Universal House of Justice to an individual believer; ‘Messages from the Universal House of Justice 1986-2001’)