“You should not gloat over your brother’s day on the day of his misfortune,
You should not rejoice over the people of Judah on the day of their perishing,
And you should not speak so arrogantly on the day of their distress.”

~Obadiah 12

Many Bible prophecies are directed toward the nation of Edom because they were distant relatives of the nations of Israel and Judah.
Edomites descended from Esau, the twin brother of Jacob (Israel). (Ge. 36:1; De. 2:4-6)
As such, God expected mutual respect between the Edomites and his people.
But this did not end up being the case; there was often war between both nations. (1 Sam. 14:47; 2 Sam. 8:13; 2 Ki. 14:7; Amos 1:11)
In this particular prophecy, Jehovah God warns the Edomites that when judgment came upon Jerusalem, they should not rejoice.
Nowadays, God’s servants do not war against others, but try to bring people a message of peace and hope. (Matt. 24:14)
Sometimes we are in situations where people who used to be friendly/receptive to God’s message are suddenly and inexplicably rude to us.
We should not rush to judge those people, saying they deserve whatever judgment may be coming their way, nor rejoice in the idea of their future calamity.