“And at daybreak the sea returned to its eitan” (Exodus 14:27), sealing the fate of the Egyptians who unwisely pursued the Israelites into the split Red Sea. Rashi explains eitan as the sea’s initial strength. No human can match the might of the sea, and so the Egyptians were washed away.
Eitan means strong, lasting. Thus Jacob blessed Joseph that his bow will stay eitan when assailed by his enemies (Genesis 49:24). The Midrash associates Abraham with Eitan in Psalms 89, whose opening line credits its composition to Eitan the Ezrahite. According to the Midrash, Abraham is Eitan, who is praising God for faithfulness to the covenant. It is only fitting that Abraham appear in the guise of Eitan, as he is discussing God’s strength and enduring love.
The Midrash, punning on the description of the Red Sea as returning to its eitan, states that the sea returned to its previous t’nai, condition. God created the Red Sea under the condition that it split during the Exodus. It was only after it fulfilled this condition that it reached its full strength. Rabbi. Shlomo Yosef Zevin reads this midrash as a metaphor for personal realisation. It is only through fulfilling goals and conditions set for us or that we set for ourselves that we can actualise our inner strength.