The corresponding letter to this chapter is Beit- house, duality as in husband and wife; also division between good and evil, etc.
Sh’mu’el Bet 2:1-7 Then it came about afterwards that David inquired of the L-RD, saying, "Shall I go up to one of the cities of Y’hudah?" And the L-RD said to him, "Go up." So David said, "Where shall I go up?" And He said, "To Hevron." So David went up there, and his two wives also, Achino’am from Yizre’el and Avigayil the widow of Naval from Karmel. And David brought up his men who were with him, each with his HOUSEHOLD; and they lived in the cities of Hevron. Then the men of Y’hudah came and there anointed David king over the house of Y’hudah. And they told David, saying, "It was the men of Yavesh-Gil’ad who buried Sha’ul." And David sent messengers to the men of Yavesh-Gil’ad, and said to them, "May you be blessed of the L-RD because you have shown this kindness to Sha’ul your lord, and have buried him. And now may the L-RD show loving kindness and truth to you; and I also will show this goodness to you, because you have done this thing. Now therefore, let your hands be strong, and be valiant; for Sha’ul your lord is dead, and also the house of Y’hudah has anointed me king over them."
Now that Sha’ul was dead, David had more freedom to move about the country. He was not handed the kingdom all at once on the contrary he first got control over his tribe, the tribe of Y’hudah.
Sh’mu’el Bet 2:8-10 But Avner the son of Ner, commander of Sha’ul's army, had taken Ish-Boshet the son of Sha’ul, and brought him over to Machanayim. And he made him king over Gil’ad, over the Ashuri, over Jezreel, over Efrayim, and over Beit-Lechem, even over all Israel. Ish-Boshet, Sha’ul's son, was forty years old when he became king over Israel, and he was king for two years. The house of Y’hudah, however, followed David.
It seems that Avner had done this thing on his own and had not inquired of the L-rd. There are consequences when we want to do things our way instead of G-d’s way. In the future there will be a false Messiah (anointed) appointed by someone who was not appointed by HaShem.
Sh’mu’el Bet 2:11-16 And the time that David was king in Hevron over the House of Y’hudah was seven years and six months. Now Avner the son of Ner, went out from Machanayim to Giv’on with the servants of Ish-Boshet the son of Sha’ul. And Yo’av the son of Zeruiah and the servants of David went out and met them by the pool of Giv’on; and they sat down, one on the one side of the pool and the other on the other side of the pool. Then Avner said to Yo’av, "Now let the young men arise and hold a contest before us." And Yo’av said, "Let them arise." So they arose and went over by count, twelve for Beit-Lechem and Ish-Boshet the son of Sha’ul, and twelve of the servants of David. And each one of them seized 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, (field of sharp swords) which is in Giv’on.
So it was 7 and a half years that David only ruled over one tribe.
This may be a slight foreshadowing of Messiah being pierced in side.
Sh’mu’el Bet 2:17-23 And that day the battle was very severe, and Avner and the men of Israel were beaten before the servants of David. Now the three sons of Zeruiah were there, Yo’av and Avishai and Asah’el; and Asah’el was as swift-footed as one of the gazelles which is in the field. And Asah’el pursued Avner and did not turn to the right or to the left from following Avner. Then Avner looked behind him and said, "Is that you, Asah’el?" And he answered, "It is I." So Avner said to him, "Turn to your right or to your left, and take hold of one of the young men for yourself, and take for yourself his spoil." But Asah’el was not willing to turn aside from following him. And Avner repeated again to Asah’el, "Turn aside from following me. Why should I strike you to the ground? How then could I lift up my face to your brother Yo’av?" However, he refused to turn aside; therefore Avner struck him in the belly with the butt end of the spear, so that the spear came out at his back. And he fell there and died on the spot. And it came about that all who came to the place where Asah’el had fallen and died, stood still.
Another foreshadowing of the spear in Messiah.
Sh’mu’el Bet 2:24-32 But Yo’av and Avishai pursued Avner, and when the sun was going down, they came to the hill of Amah, which is in front of Giach by the way of the wilderness of Giv’on. And the sons of Beit-Lechem gathered together behind Avner and became one band, and they stood on the top of a certain hill. Then Avner called to Yo’av and said, "Shall the sword devour forever? Do you not know that it will be bitter in the end? How long will you refrain from telling the people to turn back from following their brothers?" And Yo’av said, "As G-d lives, if you had not spoken, surely then the people would have gone away in the morning, each from following his brother." So Yo’av blew the trumpet; and all the people halted and pursued Israel no longer, nor did they continue to fight anymore. Avner and his men then went through the Aravah all that night; so they crossed the Yarden, walked all morning, and came to Machanayim. Then Yo’av returned from following Avner; when he had gathered all the people together, nineteen of David's servants besides Asah’el were missing. But the servants of David had struck down many of Beit-Lechem and Avner's men, so that three hundred and sixty men died. And they took up Asah’el and buried him in his father's tomb which was in Beit-Lechem. Then Yo’av and his men went all night until the day dawned at Hevron.
Here we have the house of David at war with the house of Sha’ul. Remember the letter that cooresponds to this chapter is Beit, house.