From Vladimir Moss (http://www.orthodoxchristianbooks.com)
The new calendarists have had many direct warnings from the Heavenly Church that the path they have embarked on by accepting newcalendarism-ecumenism is false. One such warning was given to the new calendarist Bishop Arsenius of Larissa on December 12/25, 1934, the feast of St. Spyridon according to the Old Calendar, but Christmas according to the new calendar.
“In the morning the bishop went by car to celebrate the Liturgy in his holy church. When he arrived there, he saw a humble, aged, gracious Bishop with a panagia on his breast. Arsenius said to him: ‘Brother, come, let’s proclaim the joyful letters of Christmas and then I will give you hospitality.’
“The humble Bishop replied: ‘You must not proclaim those letters but mine, St. Spyridon’s!’ Then Arsenius got angry and said: ‘I’m inviting you and you’re despising me. Go away then.’
“Arsenius went into the church, venerated the icons and sat in his throne. When the time for the katavasias came, he sang the first katavasia, and then told the choir to sing the second. Arsenius began to say the third, but suddenly felt anxious and unwell. He motioned to the choir to continue and went into the altar, where they asked him: ‘What’s the matter, master?’ He replied: ‘I don’t feel well.’
“When Arsenius’ indisposition increased, they carried him to his house, where his condition worsened, and the next day he died. He had been punished by God for his impious disobedience to St. Spyridon. This miracle is known by the older Orthodox faithful of Larissa.”