Dr. Couch, Obadiah 15-21 seems to be about the worldwide tribulation and the coming kingdom. Am I right? 
   
You are right on! This section starts out mentioning the great 
tribulation, the "Day of the Lord" that will fall upon "all the nations"
 (v. 15a). As the nations have been sinful so in like manner a 
retribution will fall upon them (v. 15b). As the nations have abused 
God’s holy mountain (Mount Zion in Jerusalem) by being drunk with lust 
over occupying and subverting it, so will they drink of God’s wrath and 
perish (v. 16).
      Mount Zion (in Jerusalem) will become a place of 
escape and a holy site when the Jews, a remnant of all of the children 
of Jacob, have complete control of it. (This may tell you who will end 
up finally with occupying that mountain!)
      Besides the coming of Jesus the Messiah, the 
Deliverer, there will be additional warriors who deliver the Jewish 
people at the end of the tribulation. Obadiah closes with this idea and 
writes: "The deliverers will ascend Mount Zion to judge the mountain of 
Esau, and the kingdom will be the Lord’s" (v. 21). On this verse Unger 
writes:
Obadiah concluded, as did so many of the Hebrew prophets, with a strong Messianic note centering on the promise of future blessing of regathered and restored Israel in the Kingdom promised to David (2 Sam. 7:8-15), a glorious theme that dominates Old Testament prophecy.
Thanks for asking.
Dr. Mal Couch