Abu-l-Qasim (the Prophet) said, "By Him in Whose Hand Muhammad's soul is, if you know that which I know, you would weep much and laugh little." (Using translation from Bukhārī 6637)
وَقَالَ وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَوْ تَعْلَمُونَ مَا أَعْلَمُ لَبَكَيْتُمْ كَثِيرًا وَلَضَحِكْتُمْ قَلِيلًا