Now concerning the times and the seasons, brothers and sisters, you do not need to have anything written to you. For you yourselves know very well that the day of the Lord will come like a thief in the night. 1 Thess 5:1-2
“And further, not to know when the end is, or when the day of the end will occur, is actually a good thing. If people knew the time of the end, they might begin to ignore the present time as they waited for the end days. They might well begin to argue that they should only focus on themselves. Therefore, God has also remained silent concerning the time of our death. If people knew the day of their death, they would immediately begin to neglect themselves for the greater part of their lifetime. The Word, then, has concealed both the end of all things and the time of our own death from us, for in the end of all is the end of each, and in the end of each the end of all is comprehended.
“This is so that, when things remain uncertain and always in prospect, we advance day by day as if summoned, reaching forward to the things before us and forgetting the things behind…The Lord, then, knowing what is good for us beyond ourselves, thus stabilized the disciples in a correct understanding. They, being taught, set right those of Thessalonica, who were likely to err on the very same point.”
Athanasius, Discourses Against the Arians 3.49–50.