Saul was hunting David down to kill him (1 Sm 24:12). Despite this, David refused to kill Saul when Saul was defenseless before him (1 Sm 24:8). Although David had no reservations about killing his enemies, even when defenseless, he did not kill Saul because Saul was "the Lord's anointed" (1 Sm 24:7, 11). David even "regretted that he had cut off an end of Saul's mantle" (1 Sm 24:6) because Saul was "the Lord's anointed."
In some of the greatest prophecies of the Old Testament, the Lord promised the coming of "the Anointed One," the Christ, the Messiah, Who would definitively save Israel from its enemies. Jesus is the Fulfillment of that prophecy. He is the Christ, and we who have been baptized into Him (see Rm 6:3) share in His anointing. We are "the anointed ones," that is, Christians (see 1 Jn 2:27). In His anointing, we have an exalted dignity. We Christians are the most important people in the world, and are to be revered even more than David revered Saul. In awe and respect, let us lay down our lives in love for Christ, the Anointed One, and for Christians, the anointed ones (see 1 Jn 3:16).