If repetition is the best form of emphasis, God goes overboard in the chapter-long, prophetic book of Obadiah. Between Obadiah 11 and 14, a total of four verses, the phrase "in the day" or "on the day" occurs ten times. It acts as a kind of refrain in the prophet's song of lamentation over the nation of Edom. It repetitiously reminds the reader or listener of a specific time when the Edomites' iniquity came to a head, sealing their fate.
It is also a prophetic clue. The phrase functions like a series of huge billboards, each one illuminated by glaring spotlights, but rather than displaying successive lines of a ditty, like the old Burma Shave signs, these all repeat the same phrase: "in the day"! In these verses, God is essentially shouting at us as through a loudspeaker, "This occurs 'in the day'! 'In the day' is when this happens!"
Earlier, in verse 8, God had introduced the time setting with the phrase "in that day." He refers to the time when Edom's allies betray the descendants of Esau and lay a cunning snare for them, one they fail to perceive until far too late. God informs them through the prophecy that He had had a hand in destroying Edom's wise men, who, had they been present, may have been able to discern the trap before it had been sprung.
However, the timing in verse 8 is vague, having little supporting detail to fix it in history. Subsequent verses reiterate the fact that God has one particular time in mind, to which He adds detail, alerting us to the fact that this day is not Edom's day, but his brother Jacob's day (verse 12). In addition, it is a time of distress, calamity, captivity, and destruction.
In verse 15, though, God tells us plainly, "For the day of the LORD upon all the nations is near." He has in mind a particular period of His great plan, a time when the various threads of human history, religion, culture, and thought terminate in confusion and rebellion against God, and He Himself takes center-stage to resolve the Satanic mess. Though the Edomites have gloated over Israel's misfortune on other days in the past, it will recur most egregiously in this time of the end, causing God to decree, "As you have done, it shall be done to you. . . . No survivor shall remain of the house of Esau" (verses 15, 18).
Richard T. Ritenbaugh
All About Edom (Part Five): Obadiah and God's Judgment