Laurence M. Vance quotes Bryan Fischer and refutes him:
"The Scriptures certainly know nothing of squeamishness." Take the example of King David, a man who had slain "his ten thousands" (1 Samuel 18:7), "fought with the Philistines, and brought away their cattle, and smote them with a great slaughter" (1 Samuel 23:5), smote the Amalekites "from the twilight even unto the evening of the next day: and there escaped not a man of them, save four hundred young men, which rode upon camels, and fled" (1 Samuel 30:17), "smote the Philistines from Geba until thou come to Gazer" (2 Samuel 5:25), and warred against the Philistines, Moab, Zobah, Syria, and Edom (2 Samuel 8:1, 2, 3, 5, 6, 13, 14). And remember, says Fischer, that David was a man after God’s own heart (1 Samuel 13:14).
But it is wrong to invoke the Jewish wars of the Old Testament against the heathen as a justification for the actions of the U.S. military. Although God sponsored these wars, and used the Jewish nation to conduct them, it does not follow that God sponsors American wars or that America is God’s chosen nation. The U.S. president is not King David, America is not the nation of Israel, the U.S. military is not the Lord’s army, and God never commanded any Christian to war on his behalf. The fact that King David did what he did under divine sanction has absolutely no bearing on anything the U.S. military does.
And please read the whole story of King David:
Then David the king stood up upon his feet, and said, Hear me, my brethren, and my people: As for me, I had in mine heart to build an house of rest for the ark of the covenant of the LORD, and for the footstool of our God, and had made ready for the building: But God said unto me, Thou shalt not build an house for my name, because thou hast been a man of war, and hast shed blood. (1 Chronicles 28:2-3)
King David of the Bible is not a good example after all.