Directives From the Guardian
Page 3
 

9: ALLÁH-U-ABHÁ (Bahá'í Greeting)
 
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"The Bahá'ís are free to greet each other with Alláh-u-Abhá when they meet, if they want to, but they should avoid anything which to outsiders, in a western country, might seem like some strange Oriental password. We must be very firm on principles and laws, but very normal and natural in our ways, so as to attract strangers."