As used here, “Jehovah’s day ” refers to the period that will start with the destruction of false religion and will culminate in the war of Armageddon.
فَحِينَئِذٍ ،‏ سَتَظُنُّ ٱلْأُمَمُ أَنَّهَا عَلَى وَشْكِ حَلِّ بَعْضِ مَشَاكِلِهَا ٱلْكَبِيرَةِ .‏