Ziyad related to me from Malik that he had heard that Said ibnal-Musayyab used to say, "Whoever is present at isha on Laylat al-Qadrhas taken his portion from it." (AR)
USC-MSA web (English) reference: Book 19, Hadith 17 (AR)
Arabic reference (AR): Book 19, Hadith 707 (AR)