"Despite the obvious difference between the Poor Knights of Christ and Bernard ’s Cistercian brothers (...) the intellectual continuity between these two organizations was considerable. Bernard viewed both as expressions of Christian ideals which provided a model for their contemporary peers.Cistercians were spiritual warriors, and the Templars were physical warriors fighting a fundamentally spiritual war.
Both the Cistercians and Templars lived according to very similar Rules which emphasized obedience, austerity, and focus on divine contemplation. Both communities were warned against imitating or interacting with the secular world, though Bernard showed flexibility in this regard as he developed the Templar’s Rule. (...)
(Bernard of Clairaux) had an enormous impact (...) on articulating the theology of war. Bernard’s theology of war became over the next decades integrated into the accepted Western European notion of just war. While asserting that Bernard was singularly responsible for this point of view ignores the long, building tradition which was so well expressed in his writing, his writings were undoubtedly a watershed moment in the development and articulation of Western Europe’s theology of war.
The concepts of sacred action were not static in the Middle Ages; they evolved with society, slowly in some periods and more drastically in others. The central Middle Ages witnessed the Peace of God, the Crusades, and the development of the military and mendicant orders. Though each of these movements or institutions developed for their own reasons in response to particular temporal, social, and geo-political forces, all of them are examples of the evolution of the sacred life in medieval Christianity. These movements all illustrate a trend toward social connectedness rather than isolation in the spiritual ideal; adherents were intended to be spiritually pure through isolation from the temptations of the world and the unacceptable behaviors of the common world, but they were to do so in increasingly physical continuity with the rest of society."
source "Violence and the Sacred in the Mind of Bernard of Clairvaux" by Andrew Pedry. Illustration Medieval siege source