On the special relationship between God and the Jewish people, there's a recognition of the Jews as having kept the Torah -- and criticism by the non-Jews that perhaps the Jews hadn't actually been keeping the Torah. God is willing to testify on their part, but His testimony isn't considered legitimate because of God's bias, as it were, for treating Israel as a son. So God calls the heavens and earth as witnesses -- but they are also considered suspect. Finally, God points to the non-Jewish nations of the world themselves. Plus, a reference back to preparation for Shabbat from Shabbat eve... and the granting of one small mitzvah for the non-Jews, who apparently now want in on God's command. Also, converts to join the Jewish people were not accepted during the time of King David and King Solomon -- when things are so good that the likelihood of sincerity is that much diminished. At least, until they heard of the travails of the Children of Israel... and the war of Gog and Magog. Plus, God's laughter -- rare, hopeful, or limited in some ways? Plus, remembering Jerusalem.