Ka'b said: Whoever performs ablution and performs it well, then prays the Isha prayer, and after it prays four more rak'ahs, completing their bowing and prostrations and learning what he recites in them, they will be for him equal to Laylat al-Qadr (the Night of Decree).
Al-Bukhari alluded to this in al-Tarikh, and he and others took it as evidence that Ayman's hadith about the price of the shield is munqati' (disconnected).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السرقة / 17176