Midras Mazmur 105:43: Otzar Midrashim & Pirkei DeRabbi Eliezer

Opposition 12) And a time to dance - corresponding to With a mighty hand and an outstretched arm, teaching that Israel were happy and dancing, as it says "And He led out His people with joy" (Psalms 105:43), and so too in the future they will only be redeemed with joy and gladness, as it says "And the redeemed of the Lord shall return" etc. (Isaiah 51:11), for His kindness endures forever.

Rabbi José said: All that night the Israelites were eating and drinking, rejoicing and taking wine and praising their God with a loud voice, whilst the Egyptians were crying with a bitter soul, because of the plague which came upon them suddenly, as it is said, "And there was a great cry in Egypt; for there was not a house where there was not one dead" (Ex. 12:80).