The Lord Jesus said to St. Faustina:
Before I come as the just Judge, I am coming first as the King of Mercy. Before the day of justice arrives, there will be given to people a sign in the heavens of this sort:
All light in the heavens will be extinguished, and there will be great darkness over the whole earth. Then the sign of the cross will be seen in the sky, and from the openings where the hands and the feet of the Savior were nailed will come forth great lights which will light up the earth for a period of time. This will take place shortly before the last day.
Message given to St. Faustina
Diary of Divine Mercy, n. 83