It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever prays the Isha prayer in congregation has attained his share of the Night of Decree (Laylat al-Qadr)."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7714