Influenced by the study of these writings, the exiles began to devote themselves to self-examination. This was followed by contrition for their constant disobedience and idolatry. Those who were moved to penitence by the consciousness of their great sins longed to wash away the bitter past in tears of repentance. They acknowledged that all the misfortunes that had befallen them were well deserved, for just as "the Lord of Hosts had purposed to do unto them according to their ways and according to their doings, so had He dealt with them." Many atoned sincerely; four days in the year were set apart, at first by a few, and later on by a large number of exiles, as days of mourning. These occasions were the anniversaries of Nebuchadnezzar's siege of Jerusalem in the tenth month, of the conquest of Jerusalem in the fourth month, of the destruction of Jerusalem in the fifth month, and of Gedaliah's assassination in the seventh month. At these times it became customary for the people to fast and lament, wear garments of mourning, sit in ashes and bow their heads in deep contrition. These days of mourning heralded the people's awakening; they were signs of repentance, and the first institution of national anniversaries after the captivity. This keen feeling of remorse gave birth to a new kind of psalm, which we may call the Penitential Psalm. Those who had forsaken their evil ways in turn converted others; former sinners showed other evil-doers the way to God. The number of the faithful, "those who were eager for God's word," those "who sought after God," thus gradually increased. Naturally, the Patient Sufferers (Anavim) formed the nucleus of this new party. They mourned the destruction of Jerusalem and its former glory; they were "contrite in heart," and "meek in spirit." They bore outward signs of mourning, and called themselves "the mourners of Zion." With them were associated members of noble families, who held some office or dignity at the Babylonian court. All their thoughts dwelt upon Jerusalem. They loved the stones of the Holy City, and longed to see its very ruins, lying in the dust. (Psalm cxx. 14-15.) The Levite, who, in the name of his companions in captivity, described so poetically this faithful remembrance of Jerusalem, gave utterance, in the 137th Psalm, to the sentiments of "the mourners of Zion."