Allaah (The Most High) said:

 وَلَوْ يُعَجِّلُ اللَّهُ لِلنَّاسِ الشَّرَّ اسْتِعْجَالَهُم بِالْخَيْرِ لَقُضِيَ إِلَيْهِمْ أَجَلُهُمْ

”And were Allah to hasten for mankind the evil (they invoke) as He hastens for them the good (they invoke) then they would have been ruined.”

[Soorah Yoonus: Ayah: 11]

Imaam Ibnul Qayyim (rahimahullaah) said:

The salaf (pious predecessors) said: It is the supplication of the person against himself, his children and family whilst in a state of anger. Had Allaah (The Most High) answered his invocation, it would have destroyed him and the one he supplicated against; but He (Allaah) does not answer his supplication due to His knowledge that the suppliant does not intend it.

[Source: Badaa-I At-Tafseer Al-Jaami Limaa Fassarahu Al-Imaam Ibnul Qayyim Al-Jawziyyah:page:31: Vol:2]