Abdullah bin Murrah (may Allah have mercy on him) reports from Abu Kanaf (may Allah have mercy on him), who said: We were walking with Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) in the flour market when he suddenly heard a man swearing by Surah al-Baqarah. Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: He owes the expiation of an oath for every verse of it. Al-A'mash (may Allah have mercy on him) said: I mentioned this to Ibrahim (may Allah have mercy on him), and he said that Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: Whoever swears by the Qur'an owes the expiation of an oath for every verse, and whoever disbelieves in one verse of the Qur'an has disbelieved in all of it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 19901