Public expression of religion is not appropriate in the dojo
I believe that it is inappropriate for an aikido teacher to make any references to specific religious beliefs during a class. As O Sensei stated, Aikido is not a religion. I would be very disenchanted if I were in a class in which a teacher mentioned Christianity or any other religion. I would be disenchanted NOT simply because I am not a Christian, but because Aikido should be open to people of all beliefs/non-beliefs. A teacher's exression of a particular belief links Aikido to a religion and runs a serious risk of alienating at least one student in the dojo. Keep religion off the mat.