Modified extract from Psalm 135, performed by the monks of Simonopetra Monastery (Mount Athos, Greece).
The Psalm itslef obviously isn't about war, but the performance, especially thanks to the warlike drums, give it a very military vibe, hence why the title of the video.
The painting used is called "Battle of Kulikovo" by Yuri Petrovich Pantyukhin. It was upscaled to the 16:9 format using the DALLE AI.

All rights belong to the Simonopetra Monastery
Check out the original version here :    • Video