1. When the Jewish people praise G-d in their synagogues and
    batei midrash saying, yehai shmei hagadol mevurach, G-d
    says,
    "Happy is the King who is praised so in His home". Why should a
    Father send his children into exile, and woe to the children who have been
    exiled from the table of their Father. For at that moment, G-d is
    compassionate and concerned for his children and wants to take from darkness,
    draw them to His Light, free them from their servitude and redeem them. The
    Kaddish was written in Aramaic, a language which the angels do not understand,
    so that the angels would not hear the Jewish People praising G-d and attempt
    to intervene, insisting that they don’t really mean what they are saying; that
    their words are not really coming from the heart. (Another reason that the
    Kaddish was written in Aramaic is that it reminds G-d of the destruction of
    the Beis Hamikdosh and the exile of the Jewish people from their land.
  2. Rebbe Yehoshua ben Levi said that when a person answers
    amen yehay shmei rabbah
    (Shabbos 119b) with all his might, Divine
    judgments against him are nullified. Rebbe Chiah bar Abba said in the name of
    Rebbe Yochanan that even if a person is guilty of a taint of idolatry, he is
    forgiven. According to Resh Lakish, when a person answers amen with all
    his might the gates of the garden of Eden are opened for him. Tosefos (in the
    Gemara cited above) says (citing a midrash) that when yehay shmei rabbah
    mevorach
    is recited aloud and with a raised voice, Divine edicts of
    punishments are nullified.