Ibn Rajab reported: When the treasures of Khosrau were opened for Umar ibn al-Khattab, may Allah be pleased with him, he wept and he said, “Verily, the likes of this were never opened for people but that Allah made it a source of enmity between them.”
Source: Kashf al-Kurbah 1/318
عن ابن رجب ولما فتحت كنوز كسرى على عمر بن الخطاب رضي الله عنه بكى فقال إن هذا لم يُفْتَح على قَوْمٍ قَطُّ إِلاَّ جَعَلَ اللَّهُ بَأْسَهُمْ بَيْنَهُمْ
1/318 كشف الكربة في وصف أهل الغربة