"In the overall structure of chapters 15-20 (more precisely 15:1-20:22), the literary unit describing the return of King David' (v. 11) to Jerusalem (vv. 9-43) parallels that depicting his flight (15:13-37) caused by Absalom's rebellion . . ."271
The only thing the people could do after Absalom had fallen was to return to their former king (vv. 11-12). Absalom had found his strongest support among the people of Judah. David did not want the Judahites to conclude that by supporting Absalom they had become his enemies. David extended pardon to them and informed them that he still regarded them as his closest kin. This wise political move helped unite the nation again.
". . . David's reference here [v. 12] is not to blood ties, though they may be present, but rather that mutual covenant commitments must be honored because the vows assume fidelity through thick and thin."272
David also forgave the Benjamites who had hoped for his downfall and had seen it as punishment for taking Saul's place on the throne (vv. 16-30). Shimei had actively opposed David, Ziba had misled him (apparently), and Mephibosheth had not supported him. Mephibosheth's failure to trim his toenails and his beard and to wash his clothes expressed his desire to remain ceremonially unclean while David was in exile (cf. Exod. 19:10, 14).273By forgiving all of these Benjamites David again secured the support of this difficult tribe.274A generation later, when the kingdom split in two, the tribe of Benjamin remained attached to Judah. Abishai had become an "adversary"(Heb. satan) to David in the sense that he opposed David's purpose to pardon Shimei.275
David may have divided the fields between Mephibosheth and Ziba to determine which of them was telling the truth or because he could not tell (v. 29). Solomon followed a similar procedure and threatened to divide a living baby to determine which of two mothers was telling the truth (1 Kings 3:24-25). Mephibosheth offered the entire estate to Ziba (v. 30). His action argued his innocence.276
Barzillai's support (vv. 31-39) undoubtedly represents that of others in Transjordan. By honoring him and his representative, Chimham, David cemented good relations with the tribes across the Jordan.277
The other Israelites (vv. 40-43) also rallied behind David again. The little "who loves the king most"contest they held with the Judahites illustrates their support. Thus almost the whole nation again united behind the Lord's anointed. This was a blessing from God.278
This section is a remarkable testimony to the power of forgiveness (cf. Matt. 6:12, 14-15; 18:21-22; Luke 7:47; 17:3). David had not forgiven Absalom, and perhaps the consequences of his lack of forgiveness encouraged him to take a different approach with his subjects after Absalom's death. We see in David's dealings with Amasa (vv. 11-15) that forgiveness wins over former enemies. We see in his dealings with Shimei (vv. 16-23) that forgiveness gives time for people to change. We see in his treatment of Mephibosheth and Ziba (vv. 24-30) that forgiveness placates irreconcilable adversaries. We see in his relations with Barzillai and Chimham (vv. 31-39) that forgiveness causes blessing to overflow on others. We see in the section revealing the final reactions of the Israelites and the Judahites (vv. 40-43) that forgiveness lays a strong foundation for the future.
