Scripture:

Obadiah 10-15
10 "Because of violence to your brother Jacob,
You will be covered with shame,
And you will be cut off forever.
11 "On the day that you stood aloof,
On the day that strangers carried off his wealth,
And foreigners entered his gate
And cast lots for Jerusalem —
You too were as one of them.
12 "Do not gloat over your brother's day,
The day of his misfortune.
And do not rejoice over the sons of Judah
In the day of their destruction;
Yes, do not boast
In the day of their distress.
13 "Do not enter the gate of My people
In the day of their disaster.
Yes, you, do not gloat over their calamity
In the day of their disaster.
And do not loot their wealth
In the day of their disaster.
14 "Do not stand at the fork of the road
To cut down their fugitives;
And do not imprison their survivors
In the day of their distress.
15 "For the day of the Lord draws near on all the nations.
As you have done, it will be done to you.
Your dealings will return on your own head.
NASU


Thoughts:

Edom's judgment here is attributed to how they reacted to Israel's defeat (verse 11).  The ironic thing is that Israel's defeat was because of their own sin:  Israel was rightly judged by God. 

We might tend to think that Edom's agreement with Israel's invaders and even assistance, would not be displeasing to God; was He not bringing this judgment?  But God was displeased with Edom's actions. 

We can draw a lesson from this, that even when God is bringing judgment or discipline into another's life, He wants our heart to be one of compassion for them, not celebration.  We should be concerned for their well-being (verse 11b), not gloating over their misfortune (verse 12), and not adding to their misfortune (verses 10, 13-14), for the Lord is watching and will repay (verse 15) -- believers in Christ will not be judged, but may be disciplined, themselves.

It is a natural response to be pleased when a wrong-doer "gets what they deserve," but this is not the way the Lord would have us respond.  It so easily leads us into sin.  We are wise to leave it in God's hands and thank Him that He makes all things right in His time.

Romans 12:19-21
19 Never take your own revenge, beloved, but leave room for the wrath of God, for it is written, "VENGEANCE IS MINE, I WILL REPAY," says the Lord. 20 "BUT IF YOUR ENEMY IS HUNGRY, FEED HIM, AND IF HE IS THIRSTY, GIVE HIM A DRINK; FOR IN SO DOING YOU WILL HEAP BURNING COALS ON HIS HEAD." 21 Do not be overcome by evil, but overcome evil with good.
NASU