Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[301] When the king heard that the Philistines were gathered together at the city Gazara, he sent an army against them, when Sibbechai the Hittite, one of David's most courageous men, behaved himself so as to deserve great commendation, for he slew many of those that bragged they were the posterity of the giants, and vaunted themselves highly on that account, and thereby was the occasion of victory to the Hebrews. After which defeat, the Philistines made war again; and when David had sent an army against them, Nephan his kinsman fought in a single combat with the stoutest of all the Philistines, and slew him, and put the rest to flight. Many of them also were slain in the fight. Now a little while after this, the Philistines pitched their camp at a city which lay not far off the bounds of the country of the Hebrews. They had a man who was six cubits tall, and had on each of his feet and hands one more toe and finger than men naturally have. Now the person who was sent against them by David out of his army was Jonathan, the son of Shimea, who fought this man in a single combat, and slew him; and as he was the person who gave the turn to the battle, he gained the greatest reputation for courage therein. This man also vaunted himself to be of the sons of the giants. But after this fight the Philistines made war no more against the Israelites.