Bede : David then girded himself with Saul's sword, etc. The sword of Saul is the law, which was given through Moses: the garment of David, the work of grace and truth, which was made through Jesus Christ. Therefore, David, girded with the sword of Saul over his own garment, began to test whether he could proceed if armed. For he said he was not accustomed. Observing for a time the carnal commandment of the law, while the spiritual gift of grace was not yet manifested to the peoples, the Savior began to gradually show that his body, which is the Church, burdened with the ceremonies of the law, could not suffice for the spiritual combat, especially among those who, called from the Gentiles to the faith, had no custom at all of enduring the more severe decrees of the law. Finally, the apostle Peter, contesting and criticizing those who wanted to burden the members of David advancing towards the struggle against the giant with Saul's arms, said: "Now therefore why do you tempt God, by imposing a yoke upon the neck of the disciples, which neither our fathers nor we were able to bear? But we believe that through the grace of the Lord Jesus we shall be saved, just as they will." — Commentary on Samuel