The oracle against Moab is organized in a fairly neat chiastic structure:

A. Oracle against Moab - wailing and lamentation, 15:1-4

B. “My heart cries,” 15:5

C. Green things wither, 15:6

D. Riches of Moab taken away, 15:7-9

E. Refuge for outcasts in tent of David, 16:1-5

D’. Pride of Moab, 16:6

C’. Fields and vines struck, 16:7-8

B’. “I weep bitterly,” 16:9-12

A’. Word that Yahweh spoke, 16:13-14.

One of the points this structure clarifies is the identity o fthe “I” in 15:5. By linking it with 16:9-12, it becomes obvious that Yahweh Himself joins in the lamentation over Moab.