The Bible says that to avoid sin, remember death.
“In all you do, remember the end of your life, and you will never sin.”
– Sirach 7:36
The phrase originated in ancient Rome: as a Roman general was parading through the streets during a victory triumph, standing behind him was his slave, tasked with reminding the general that, although at his peak today, tomorrow he could fall. The servant conveyed this by whispering to him,
Tertullian tells us is his Apologeticus, that the slave said,
“Respice post te! Hominem te esse memento! Memento mori!”
“Look behind you! Remember that you are a man! Remember that you will die!”