Musnad Ahmad 1012:52

Hassan narrated to us, Ibn Lahi'ah narrated to us, Al-Harith ibn Yazid narrated to us, from Ali ibn Rabah, that he heard Junadah ibn Abi Umayyah say: I heard Ubadah ibn al-Samit say: A man came to the Prophet, may God bless him and grant him peace, and said: "O Prophet of God, which deed is best?" He said: "Faith in God, belief in Him, and striving in His path." He said: "I want something easier than that, O Messenger of God." He said: "Generosity and patience." He said: "I want something easier than that, O Messenger of God." He said: "Do not accuse God regarding anything He has decreed for you."