Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates: "When the opening verses of Surah al-Muzzammil were revealed, the people's standing in prayer at night was like their standing in Ramadan, or nearly like it, and between the revelation of the beginning of the surah and its end there was an interval of one year."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12821