Another matter, “then Moses…sang” – that is what is written: “But I will sing of Your might; I will sing aloud of Your mercy in the morning, [You were a fortress for me and a refuge on the day of my distress]” (Psalms 59:17). “I will sing of Your might” – in the future, as it is stated: “[And in that day you shall say…] Behold, God is my salvation I will trust and I will not fear [for God is my might and song]” (Isaiah 12:1–2).
“I will sing aloud of Your mercy in the morning” – [in] that morning of the day of judgment, as it is stated: “The watchman said: Morning comes and also night” (Isaiah 21:12). “You were a fortress for me” in Edom; “and a refuge on the day of my distress” in Gog and Magog. Alternatively, “but I will sing of Your might” (Psalms 59:17) – when [did this occur]? When Israel was standing at the sea and reciting song, as it is stated: “Then Moses…sang.”
What did they say? “The Lord is my strength” (Exodus 15:2). “I will sing aloud of Your mercy in the morning,” – that morning when You looked down on the Egyptian encampment, as it is stated: “It was at the morning watch, [and the Lord looked down at the camp of Egypt]” (Exodus 14:24). Alternatively, that morning that You brought the manna down for us, as it is stated: “In the morning there was a layer of dew” (Exodus 16:13).
Alternatively, that morning of the giving of the Torah, as it is stated: “It was on the third day, when it was morning” (Exodus 19:16). “You were a fortress for me” with Pharaoh and Egypt, “and a refuge on the day of my distress” with Amalek.