Keep our Sword Sheathed

(image credit)

In T'ai Chi we may greet each other like so.

First, it's a gesture of peace to keep our sword sheathed.  But just as it's our sign of respect for others, others must reciprocate with the same gesture.  

Second, it's a reminder that it's still a sword, so others never lose track of that.  A samurai can unsheathe his sword at a moment's notice.