Our sages say that at the see, the ministering angels wished to sing, but God objected, saying: "The work of My hands is drowning, and you wish to sing!" The drowning of the Egyptians prevented the angels, but no the Israelites, from singing. The reason is that the angels wished to sing of Israel's deliverance; but Israel sang of the revelation of God's loftiness.
(from "Living Kabbalah" by Simcha Benyosef)
(from "Living Kabbalah" by Simcha Benyosef)