The Prophet ﷺ said, "If you knew that which I know, you would laugh little and weep much." (Using translation from Bukhārī 6486)  

عَنِ النَّبِيِّ ﷺ قَالَ «لَوْ تَعْلَمُونَ مَا أَعْلَمُ لَضَحِكْتُمْ قَلِيلًا وَلَبَكَيْتُمْ كَثِيرًا»  

A similar tradition has also been narrated by Anas from the Prophet ﷺ through a different chain of narrators. (Using translation from Abū Dāʾūd 390)  

عَنِ النَّبِيِّ ﷺ بِمِثْلِ هَذَا