Qatadah said: "In the reading of Sayyiduna Ibn Mas'ud (may Allah be pleased with him) it is: 'famdu ila dhikrillah' (proceed to the remembrance of Allah), and it is like the saying of Allah: 'Indeed, your efforts are diverse' [Surah al-Layl: 4]."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9506