Blood, fire, clouds
Blood and fire and clouds of smoke
are the wonders which Joel foresaw on earth.
The blood is the Incarnation;
the fire is the Godhead;
the clouds of smoke are the Holy Spirit,
Who descended upon the Virgin
and has made the world fragrant.
Great is the mystery of your Incarnation!
O Lord, Glory to You!
— Praises, Matins for Sunday after Nativity
The prophecy is from Joel chapter 2, quoted in Acts chapter 2.