“The Lord said to Moses: ‘Why are you crying out to Me? Speak to the children of Israel and have them set forth’” (Exodus 14:15). “The Lord said to Moses: ‘Why are you crying out to Me?’” That is what is written: “They cried out and the Lord heard” (Psalms 34:18).
Why is this so? Isaac bequeathed two inheritances to his two sons: He bequeathed the voice to Jacob, as it says: “The voice is the voice of Jacob” (Genesis 27:22). He bequeathed the hands to Esau, as it is stated: “But the hands are the hands of Esau” (Genesis 27:22). Esau was proud of his inheritance, as it is stated: “Edom said to him: 'You shalt not pass through me, lest with a sword [I will come out against you’]” (Numbers 20:18).
Jacob was proud of his inheritance, as it is stated: “We cried out to the Lord, God of our fathers” (Deuteronomy 26:7). In the future, both of them will receive their rewards. Esau will receive his reward, as it is stated: “As My sword has drunk its fill in the heavens; behold, it will descend upon Edom” (Isaiah 34:5). Jacob will receive his reward, as it is stated: “The voice of gladness, the voice of joy” (Jeremiah 33:11).
This is why it is written: “They cried out and the Lord heard,” because the children of Israel cried out at the sea, as it is stated: “The children of Israel cried out to the Lord” (Exodus 14:10). The Holy One blessed be He heard their prayer and said to Moses: “Why are you crying out to Me? I already heard their cry.” – “Speak to the children of Israel and have them set forth.”