O Sanction the prayer of the Knights Templar on their sword.

O sanction, In nomine dei. O Holy One, in your name Lord

A prayer of penance. Lord, what I do, I do in your sight. In this way they were accountable to God.

Knights Templar prayed before a battle. In this way, they received absolution for what was to come. They prayed for steadfastness, pure intention. For grace, not for bloodlust.

They knew: what we are going to do is not clean. A prayer of penance on the sword is a Holy invocation. The sword is not only an instrument of war, it is an anchor.

That is why you also see crosses on the other side of the sword

Not to be confused with the OS of prayer dedicated to Mary. O Sanctissima. Prayer to Mary for calm. Not really conducive to a battlefield.