It is narrated from Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Shall I not show you a treasure from the treasures of Paradise?" I said: "Certainly, O Messenger of Allah." He (peace and blessings be upon him) said: "La hawla wa la quwwata illa billah" (that is, there is no power to avoid evil and no strength to do good except through Allah).
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17506