It is reported about Sayyiduna Abdullah bin Unays (may Allah be pleased with him) that he submitted: "O Messenger of Allah! Tell me, on which night should Laylat al-Qadr be sought?" The Prophet (peace and blessings be upon him) said: "Were it not for the fear that people would abandon prayer altogether and pray only on that night, I would have told you."
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and its chain is hasan (good).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصيام / 5062