Angels do not possess the song of Malchus (kingship). Hashem prefers the song of the Jewish people on Shabbos. A Kallah (bride) gives over everything to her husband and her husband trusts her completely. The greatest song that can be sung is by a Jew, stained by sin, who remains faithful to Hashem. Shabbos is coming home. Everything on Shabbos is illuminated with the quality of being a Kallah. Tu B’Shvat is the time to daven for a beautiful esrog. All of the Jewish people are beautiful in the eyes of Hashem.