Odd Compassion For An Enemy

Isaiah 15
1 The burden of Moab. Because in the night Ar of Moab is laid waste, and brought to silence; because in the night Kir of Moab is laid waste, and brought to silence:
2 he is gone up to Bajith, and to Dibon, the high places, to weep: Moab shall howl over Nebo, and over Me'deba: on all their heads shall be baldness, and every beard cut off.

This is about the total destruction of Israel's enemy, Moab.  And it seems odd that the prophet, in verse 5 seems to take pity, in a plaintive, heartfelt way, on this enemy:
 
More From Isaiah 15
5 My heart shall cry out for Moab....

But, in the end, the Bible is about God's justice:

Amos 2
1 Thus saith the LORD; For three transgressions of Moab, and for four, I will not turn away the punishment thereof; because he burned the bones of the king of Edom into lime:
2 but I will send a fire upon Moab, and it shall devour the palaces of Kir'i-oth: and Moab shall die with tumult, with shouting, and with the sound of the trumpet:
3 and I will cut off the judge from the midst thereof, and will slay all the princes thereof with him, saith the LORD.

Somehow, this makes me think of the grace that finally came to the gentiles, in the New Testament.