Biblical Context:
The account of David mourning for Abner is found in 2 Samuel 3:31-39. Abner, the son of Ner, was the commander of Saul's army and a significant figure in the power dynamics following King Saul's death. After Saul's demise, Abner initially supported Ish-bosheth, Saul's son, as king over Israel. However, due to a falling out with Ish-bosheth, Abner sought to transfer the allegiance of Israel to David, who was reigning over Judah in Hebron.

The Death of Abner:
Abner's death was a result of treachery. Joab, the commander of David's army, killed Abner in Hebron. Joab's actions were motivated by a personal vendetta, as Abner had previously killed Joab's brother, Asahel, in battle (2 Samuel 2:23). Despite Abner's intentions to bring the kingdom under David's rule, Joab's act of vengeance was carried out without David's consent or knowledge.

David's Response:
Upon learning of Abner's death, David's response was one of genuine mourning and public lamentation. David's actions were significant in demonstrating his integrity and his desire for justice, as well as his respect for Abner's position and contributions. David's lamentation is recorded in 2 Samuel 3:33-34: "Should Abner die the death of a fool? Your hands were not bound, your feet were not fettered; as one falls before the wicked, you have fallen."

David ordered Joab and all the people with him to tear their clothes, put on sackcloth, and mourn for Abner. David himself followed the bier, weeping at Abner's grave, which further emphasized his sorrow and the gravity of the situation. The king's lament and his refusal to eat until sunset (2 Samuel 3:35) were public demonstrations of his grief and his disapproval of Joab's actions.

Significance:
David's mourning for Abner served multiple purposes. It was a personal expression of grief for a fallen leader and a political statement to the tribes of Israel. By publicly mourning Abner, David distanced himself from the murder, thereby maintaining his reputation as a just and righteous leader. This act helped to solidify David's position as the rightful king over all Israel, as it reassured the northern tribes of his integrity and his commitment to justice.

David's lamentation also highlighted the theme of divine justice and the sanctity of life, as he declared, "May the LORD repay the evildoer according to his wickedness!" (2 Samuel 3:39). This statement underscored David's reliance on God to bring about justice, rather than taking matters into his own hands.

Theological Implications:
From a theological perspective, David's mourning for Abner reflects the biblical principles of justice, mercy, and the value of human life. It illustrates the importance of leaving vengeance to God and maintaining righteousness in leadership. David's actions serve as a model for godly leadership, emphasizing the need for leaders to act with integrity, even in complex and challenging situations.

David's lament for Abner is a poignant reminder of the brokenness of human relationships and the consequences of sin, yet it also points to the hope of redemption and the ultimate justice that God will bring.