2 Samuel 23:8-12 – These re the names of David’s mightiest men.  The first was Jasobeam the Hacmonite, who was commander of the Three – the three greatest warriors among David’s men.  He once used his spear to kill eight hundred enemy warriors in a single battle. 
Next in rank among the Three was Eleazar son of Dodai, a descendant of Ahoah.  Once Eleazar and David stood together against the Phillistines when the entire Israelite army had fled.  He killed Phillistines until his hand was too tired to lift his sword, and the Lord gave him a great victory that day.  The rest of the army did not return until it was time to collect the plunder. 
Next in rank was Shammah son of Agee from Harar.  One time the Phillistines gathered at Lehl and attacked the Israelites in a field full of lentils.  The Israelite army fled, but Sammah held his ground in the middle of the field and beat back the Phillistines.  So the Lord brought about a great victory.
To protect a kingdom and your livelihood, you need the best of the best.  You need warriors who are at the top of their game, and are willing to risk it no matter what.  David picked these three guys as his personal secret service, and there is no confusion as to why he chose these three.  At this point in the Bible, David was king, and so we know he had enemies such as the Phillistines.
Jasobeam
I always thought one man killing hundreds was only in Jackie Chan movies, but now I can see where they might get their inspiration.  Jasobeam is the commander of the elite group.  I would dare to compare this warrior to the commander of the Delta Force.  Killing eight hundred trained warriors singlehandedly is not something to laugh at.
Eleazar
Eleazar is a warrior of courage and resolve.  He knew who his enemy was, and he knew what was at stake.  Regardless of the opposition he faced, he stood firm, fighting off his adversaries until he was completely out of strength, while the rest of the army fled.  If a whole army retreats, that usually means the opposition is much more powerful and resourceful than they, but despite that uncertainty, one man stands against it anyway.
Shammah
Shammah is another warrior not afraid to stand up against formidable foes.  Again, as a full army runs away from the battle, one man stands alone.  The verse mentions he stood his ground, but does not imply he killed anyone.  It may be much easier to kill a multitude of warriors by yourself than to influence them to back off.
These men did not get to this level in their own might.  When they chose to step out in faith and to accomplish their mission, the Lord is the one that gave them the great victory.  We are vessels for God.  He is the one that produces the results.  That is good news to me.  It means that He is in complete control over our every situation, big or small.  When you find yourself facing great opposition, and you are standing alone, stand firm and risk it all for the name of Christ.