All praise be to Allah, the Lord of the Universe" (1) is the epitome or basis of the Qur'an, the epitome or basis of the Book, and the seven oft-repeated verses.  

قَالَ رَسُولُ اللَّهِ ﷺ { الْحَمْدُ لِلَّهِ رَبِّ الْعَالَمِينَ } أُمُّ الْقُرْآنِ وَأُمُّ الْكِتَابِ وَالسَّبْعُ الْمَثَانِي  

I prayed ant then I came to him. He asked: What prevented you from answering me ? He replied: I was praying. He said: Has not Allah said: "O you who believe, respond to Allah and the Apostle when he calls you to that which gives you life ? (8:24) Let me teach you the greatest surah from the Qur'an or in the Qur'an (the narrator Khalid doubted) before I leave the mosque. I said: (I shall memorize) your saying. He said: It is: "Praise be to Allah, the Lord of the Universe" which is the seven oft-repeated verses, and the mighty Qur'an.  

أَنَّ النَّبِيَّ ﷺ مَرَّ بِهِ وَهُوَ يُصَلِّي فَدَعَاهُ قَالَ فَصَلَّيْتُ ثُمَّ أَتَيْتُهُ قَالَ فَقَالَ مَا مَنَعَكَ أَنْ تُجِيبَنِي قَالَ كُنْتُ أُصَلِّي قَالَ أَلَمْ يَقُلِ اللَّهُ ﷻ { يَا أَيُّهَا الَّذِينَ آمَنُوا اسْتَجِيبُوا لِلَّهِ وَلِلرَّسُولِ إِذَا دَعَاكُمْ لِمَا يُحْيِيكُمْ } لأُعَلِّمَنَّكَ أَعْظَمَ سُورَةٍ مِنَ الْقُرْآنِ أَوْ فِي الْقُرْآنِ شَكَّ خَالِدٌ قَبْلَ أَنْ أَخْرُجَ مِنَ الْمَسْجِدِ قَالَ قُلْتُ يَا رَسُولَ اللَّهِ قَوْلَكَ قَالَ { الْحَمْدُ لِلَّهِ رَبِّ الْعَالَمِينَ } وَهِيَ السَّبْعُ الْمَثَانِي الَّتِي أُوتِيتُ وَالْقُرْآنُ الْعَظِيمُ