"Saul and Jonathan, beloved and lovely! In life and in death they were not divided; they were swifter than eagles, they were stronger than lions. O daughters of Israel, weep over Saul, who clothed you with crimson, in luxury, who put ornaments of gold on your apparel. How the mighty have fallen in the midst of the battle! Jonathan lies slain upon your high places. I am distressed for you, my brother Jonathan; greatly beloved were you to me; your love to me was wonderful, passing the love of women. How the mighty have fallen, and the weapons of war perished!" (2 Samuel 1:23-27, NRSV)
Saul and Jonathan were lovely and pleasant in their lives, and in their death they were not divided: they were swifter than eagles, they were stronger than lions. Ye daughters of Israel, weep over Saul, who clothed you in scarlet, with other delights, who put on ornaments of gold upon your apparel. How are the mighty fallen in the midst of the battle! O Jonathan, thou wast slain in thine high places. I am distressed for thee, my brother Jonathan: very pleasant hast thou been unto me: thy love to me was wonderful, passing the love of women. How are the mighty fallen, and the weapons of war perished! (2 Samuel 1:23-27, KJV)
David movingly laments the death of his bestie, Jonathan, and of Saul. It's also a way of saying, "Hey, I wasn't an enemy of these guys—forget about that period of bad-blood between me and Saul."
Abner said to Joab, "Let the young men come forward and have a contest before us." Joab said, "Let them come forward." So they came forward and were counted as they passed by, twelve for Benjamin and Ishbaal son of Saul, and twelve of the servants of David. Each grasped his opponent by the head, and thrust his sword in his opponent's side; so they fell down together. Therefore that place was called Helkath-hazzurim, which is at Gibeon. The battle was very fierce that day; and Abner and the men of Israel were beaten by the servants of David. (2 Samuel 2:14-17, NRSV)
And Abner said to Joab, Let the young men now arise, and play before us. And Joab said, Let them arise. Then there arose and went over by number twelve of Benjamin, which pertained to Ishbosheth the son of Saul, and twelve of the servants of David. And they caught every one his fellow by the head, and thrust his sword in his fellow's side; so they fell down together: wherefore that place was called Helkathhazzurim, which is in Gibeon. And there was a very sore battle that day; and Abner was beaten, and the men of Israel, before the servants of David. (2 Samuel 2:14-17, KJV)
It's unclear whether this fight between the twelve youths was meant to escalate into a full battle between both sides or not.
David inquired of the Lord, "Shall I go up against the Philistines? Will you give them into my hand?" The Lord said to David, "Go up; for I will certainly give the Philistines into your hand." So David came to Baal-perazim, and David defeated them there. He said, "The Lord has burst forth against my enemies before me, like a bursting flood." Therefore that place is called Baal-perazim. The Philistines abandoned their idols there, and David and his men carried them away. (2 Samuel 5:19-21, NRSV)
And David enquired of the Lord, saying, Shall I go up to the Philistines? wilt thou deliver them into mine hand? And the Lord said unto David, Go up: for I will doubtless deliver the Philistines into thine hand. And David came to Baalperazim, and David smote them there, and said, The Lord hath broken forth upon mine enemies before me, as the breach of waters. Therefore he called the name of that place Baalperazim. And there they left their images, and David and his men burned them. (KJV 5:19-21)
This is a good example of the religious aims of these wars, the way a formless God triumphs over gods with images.
David also struck down King Hadadezer son of Rehob of Zobah, as he went to restore his monument at the river Euphrates. David took from him one thousand seven hundred horsemen, and twenty thousand foot soldiers. David hamstrung all the chariot horses, but left enough for a hundred chariots. When the Arameans of Damascus came to help King Hadadezer of Zobah, David killed twenty-two thousand men of the Arameans. Then David put garrisons among the Arameans of Damascus; and the Arameans became servants to David and brought tribute. The Lord gave victory to David wherever he went. David took the gold shields that were carried by the servants of Hadadezer, and brought them to Jerusalem. From Betah and from Berothai, towns of Hadadezer, King David took a great amount of bronze. (2 Samuel 8:3-8, NRSV)
David smote also Hadadezer, the son of Rehob, king of Zobah, as he went to recover his border at the river Euphrates. And David took from him a thousand chariots, and seven hundred horsemen, and twenty thousand footmen: and David houghed all the chariot horses, but reserved of them for an hundred chariots. And when the Syrians of Damascus came to succour Hadadezer king of Zobah, David slew of the Syrians two and twenty thousand men. Then David put garrisons in Syria of Damascus: and the Syrians became servants to David, and brought gifts. And the Lord preserved David whithersoever he went. And David took the shields of gold that were on the servants of Hadadezer, and brought them to Jerusalem. And from Betah, and from Berothai, cities of Hadadezer, king David took exceeding much brass. (2 Samuel 8:3-8, KJV)
These lines celebrate David's achievements. Think of them as a brochure listing his greatest military victories.
The Arameans fled before Israel; and David killed of the Arameans seven hundred chariot teams, and forty thousand horsemen, and wounded Shobach the commander of their army, so that he died there. When all the kings who were servants of Hadadezer saw that they had been defeated by Israel, they made peace with Israel, and became subject to them. So the Arameans were afraid to help the Ammonites any more. (2 Samuel 10:18-19, NRSV)
And the Syrians fled before Israel; and David slew the men of seven hundred chariots of the Syrians, and forty thousand horsemen, and smote Shobach the captain of their host, who died there. And when all the kings that were servants to Hadarezer saw that they were smitten before Israel, they made peace with Israel, and served them. So the Syrians feared to help the children of Ammon any more. (2 Samuel 10:18-19, KJV)
This is yet more from the triumphal period of David's successes in war. He's still riding high.
But the man said to Joab, "Even if I felt in my hand the weight of a thousand pieces of silver, I would not raise my hand against the king's son; for in our hearing the king commanded you and Abishai and Ittai, saying: For my sake protect the young man Absalom! On the other hand, if I had dealt treacherously against his life (and there is nothing hidden from the king), then you yourself would have stood aloof." Joab said, "I will not waste time like this with you." He took three spears in his hand, and thrust them into the heart of Absalom, while he was still alive in the oak. And ten young men, Joab's armor-bearers, surrounded Absalom and struck him, and killed him. (2 Samuel 18:12-15, NRSV)
And the man said unto Joab, Though I should receive a thousand shekels of silver in mine hand, yet would I not put forth mine hand against the king's son: for in our hearing the king charged thee and Abishai and Ittai, saying, Beware that none touch the young man Absalom. Otherwise I should have wrought falsehood against mine own life: for there is no matter hid from the king, and thou thyself wouldest have set thyself against me. Then said Joab, I may not tarry thus with thee. And he took three darts in his hand, and thrust them through the heart of Absalom, while he was yet alive in the midst of the oak. And ten young men that bare Joab's armour compassed about and smote Absalom, and slew him. (2 Samuel 18:12-15, KJV)
David's viewpoint is fatherly—he still loves his son. But Joab is probably thinking more politically: he wants to show that you can't rebel against the king, tear the country in two, and still come through it alive.
Joab answered, "Far be it from me, far be it, that I should swallow up or destroy! That is not the case! But a man of the hill country of Ephraim, called Sheba son of Bichri, has lifted up his hand against King David; give him up alone, and I will withdraw from the city." The woman said to Joab, "His head shall be thrown over the wall to you." Then the woman went to all the people with her wise plan. And they cut off the head of Sheba son of Bichri, and threw it out to Joab. So he blew the trumpet, and they dispersed from the city, and all went to their homes, while Joab returned to Jerusalem to the king. (2 Samuel 20:20-22, NRSV)
And Joab answered and said, Far be it, far be it from me, that I should swallow up or destroy. The matter is not so: but a man of mount Ephraim, Sheba the son of Bichri by name, hath lifted up his hand against the king, even against David: deliver him only, and I will depart from the city. And the woman said unto Joab, Behold, his head shall be thrown to thee over the wall. Then the woman went unto all the people in her wisdom. And they cut off the head of Sheba the son of Bichri, and cast it out to Joab. And he blew a trumpet, and they retired from the city, every man to his tent. And Joab returned to Jerusalem unto the king. (2 Samuel 20:20-22, KJV)
Joab thought it was pretty important to kill Absalom, a rebellion's leader. Here, he also approaches that as the main issue: if you cut off the head of the rebellion (in this case, literally) the body will die.
After this a battle took place with the Philistines, at Gob; then Sibbecai the Hushathite killed Saph, who was one of the descendants of the giants. Then there was another battle with the Philistines at Gob; and Elhanan son of Jaare-oregim, the Bethlehemite, killed Goliath the Gittite, the shaft of whose spear was like a weaver's beam. There was again war at Gath, where there was a man of great size, who had six fingers on each hand, and six toes on each foot, twenty-four in number; he too was descended from the giants. When he taunted Israel, Jonathan son of David's brother Shimei, killed him. These four were descended from the giants in Gath; they fell by the hands of David and his servants. (2 Samuel 21:18-22, NRSV)
And it came to pass after this, that there was again a battle with the Philistines at Gob: then Sibbechai the Hushathite slew Saph, which was of the sons of the giant. And there was again a battle in Gob with the Philistines, where Elhanan the son of Jaareoregim, a Bethlehemite, slew the brother of Goliath the Gittite, the staff of whose spear was like a weaver's beam. And there was yet a battle in Gath, where was a man of great stature, that had on every hand six fingers, and on every foot six toes, four and twenty in number; and he also was born to the giant. And when he defied Israel, Jonathan the son of Shimeah the brother of David slew him. These four were born to the giant in Gath, and fell by the hand of David, and by the hand of his servants. (2 Samuel 21:18-22, KJV)
The fact that these warriors are defeating giants makes them all the more impressive and legendary as fighters.
Now there was a famine in the days of David for three years, year after year; and David inquired of the Lord. The Lord said, "There is bloodguilt on Saul and on his house, because he put the Gibeonites to death." So the king called the Gibeonites and spoke to them. (Now the Gibeonites were not of the people of Israel, but of the remnant of the Amorites; although the people of Israel had sworn to spare them, Saul had tried to wipe them out in his zeal for the people of Israel and Judah.) (2 Samuel 21:1-2, NRSV)
Then there was a famine in the days of David three years, year after year; and David enquired of the Lord. And the Lord answered, It is for Saul, and for his bloody house, because he slew the Gibeonites. And the king called the Gibeonites, and said unto them; (now the Gibeonites were not of the children of Israel, but of the remnant of the Amorites; and the children of Israel had sworn unto them: and Saul sought to slay them in his zeal to the children of Israel and Judah.) (2 Samuel 21:1-2, KJV)
All is apparently not fair in love and war—Saul wasn't fair, persecuting and killing the members of an innocent people, and so now, his family pays for his crimes.