It is narrated from Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) was asked: "Who among people are tried most severely?" He (peace and blessings be upon him) said: "The prophets, then those who are best (in rank) after them, then those who are best after them. When a man is firm in his religion, he is tried according to the measure of his religion: the one whose religion is solid, his trial is severe, and the one whose religion is weak, his trial is (correspondingly) lighter." This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim).