Sahih Muslim Book - 54, Hadith - 7550

حَدَّثَنِى يُونُسُ بْنُ عَبْدِ الأَعْلَى الصَّدَفِىُّ أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ أَخْبَرَنِى عَمْرُو بْنُ الْحَارِثِ عَنْ سَعِيدِ بْنِ أَبِى هِلاَلٍ عَنْ عَوْنِ بْنِ عَبْدِ اللَّهِ عَنْ أَبِيهِ أَنَّ ابْنَ مَسْعُودٍ قَالَ مَا كَانَ بَيْنَ إِسْلاَمِنَا وَبَيْنَ أَنْ عَاتَبَنَا اللَّهُ بِهَذِهِ الآيَةِ (أَلَمْ يَأْنِ لِلَّذِينَ آمَنُوا أَنْ تَخْشَعَ قُلُوبُهُمْ لِذِكْرِ اللَّهِ) إِلاَّ أَرْبَعُ سِنِينَ.

Ibn Mas'ud, may Allah be pleased with him, said: "There was no more than four years between the time when we became Muslim, and the time when Allah rebuked us with this Verse: Has not the time come for the hearts of those who believe to be affected by Allah's Reminder..."