Rabbi Abba taught: "Gird thy sword upon thy thigh, O valorous one; thy glory and thy majesty," (Tehillim, 45:4.)
The main point of the matter, is that G-d has given the sign of the holy Brit, and stamped it upon men for them to guard it, and not blemish it - it being the stamp of the King. He who blemishes it, behold, the sword which avenges the blemish to the Brit is raised up against him, (Vayikra, 26:25,) to avenge the blemish to the holy Brit which is impressed on him and which he impaired.
He who desires to safeguard this place should hurry and make a rectification-tikun on himself. When the evil inclination gains strength over him, he should picture the sword that is girded on the thigh to punish anyone who blemishes this place. This is the reason it says: "Gird thy sword upon thy thigh, O valorous one." This one is called valorous, and this is his "glory and majesty."