It is narrated from Sayyiduna Qais bin Sa'd that once his father sent him to serve the Prophet (peace be upon him). When the Prophet (peace be upon him) arrived, I had already performed two rak'ahs. The Prophet (peace be upon him) tapped my foot and said, "Shall I not tell you about one of the gates of Paradise?" I replied, "Why not!" The Prophet (peace be upon him) said, "That gate is: La hawla wa la quwwata illa billah."
Hadith Referenceمسند احمد / مسند المكيين / 15480
Hadith Gradingحکم دارالسلام:حسن الغيره، وهذا إسناد ضعيف لم يذكر سماع ميمون بن أبى شبيب من قيس بن سعد، وهو كثير الإرسال