Rashi on the Prophets and Writings

Aha! An expression of joy.
because it was possessed [Heb. נִחָל.] Because it was possessed (נִנְחָל) and became an inheritance for others.

to the children of the East The Chaldeans and Aram are to the east.

Because you clapped with your hand and stamped with your foot for joy. Although he said this at the beginning of the Book in reference to mourning (6:11): “Strike with your hand and stamp with your foot, and say, Ah!” there are things that are done for [both] mourning and joy, but the idea behind them is not the same. Similarly, flutes for a bride and for the dead.
and stamped [Heb. וְרַקְעֲךָ,] an expression of stamping.
with all the disdain [Heb. שָּׁאטְךָ,] interpreted as an expression of disdain, like (Gen. 25:34): “and Esau despised,” which Onkelos renders: וְשָׁט, but I say that שָּׁאטְךָ is an expression of lust, golozemant or golosement in Old French, ardent desire, gluttony.

Behold the house of Judah is like all the nations The love of the Holy One, blessed be He, has been annulled from them, and they are rejected, to be given into the hands of Nebuchadnezzar like the other nations. The Midrash Aggadah (see Lam. Rabbah, Proem 9) [says] that they entered the Temple and peeled off the pictures of the cherubim that Solomon had painted on the wall of the Temple (I Kings 7:36): “according to the attachment of a man and the joining, etc.” They took them outside and said, “Look at what these [Jews], who were showing themselves as decent people, were occupied with.”

behold I will expose the fortresses of the land of Moab that are on the border at the end of their boundary; that is the flank, the end of the boundary of their land, like (Exod. 27:15): “And on the other side,” to the flank, which Targum [Jonathan] translates לְעִיבְרָא, to the side.

To the children of the East I will expose them so that they should come upon the children of Ammon through the land of Moab.

and Dedan [Heb. וּדְדָנֶה,] the inhabitants of Dedan.

by the hand of My people Israel They will be My agents to wreak My vengeance.

Because the Philistines acted with vengeance With hatred and with rigor, like a man who wreaks vengeance upon his enemy.

the Cherethites [Heb. כְּרֵתִים,] a nation deserving of being cut off (Targum). But I say, because I saw elsewhere that Scripture calls the Philistines כְּרֵתִים (Zeph. 2:5): “Woe to the inhabitants of the seacoast, the nation of (כְּרֵתִים),” and it does not give any other nation this appellation, it appears to me that there is a region of Philistia called Chereth, and so I find in the Book of (I) Samuel (30:14), concerning the group that set fire to Ziklag: “We made a raid on the south of the Cherethites.”
the seacoast [Heb. חוֹף הַיָם,] marche in Old French, frontier, borderland. They are Philistines, who live in the southwestern corner of the land of Israel on the Western (Mediterranean) Sea.