Zirr bin Hubaysh (may Allah have mercy on him) said: Ubayy bin Ka'b (may Allah be pleased with him) said to me: "How much of Surah al-Ahzab do you recite? How many (verses) do you count it as?" I said: Seventy-three verses. He said: "It is equal to Surah al-Baqarah, and in it was this verse: 'When the married man and the married woman commit adultery, stone them; this is a punishment from Allah, and Allah is Almighty, All-Wise.'"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 16911