Tradition
St. Cyril of Jerusalem
Catechetical Lectures
Book 15 › Introduction
On the Clause, And Shall Come in Glory to Judge the Quick and the Dead; Of Whose Kingdom There Shall Be No End.
Daniel 7:9-14
I beheld till thrones were placed, and one that was ancient of days did sit, and then, I saw in a vision of the night, and behold one like the Son of Man came with the clouds of heaven, etc.
Source: Catechetical Lectures (New Advent)