From Egypt I called out to God. "Mitzrayim" is what the Jewish people call the Lord in all languages, and He answers them. They called Him "Shaddai" in the fields, as it says, "May El Shaddai bless you" (Genesis 28:3), and He answered them in the fields, as it says, "I am El Shaddai; be fruitful and multiply" (ibid. 35:11). They called Him "Elohim," as it says, "O Lord, what can You give me?" (Exodus 2:22), and He answered them, as it says, "And their cry for help rose up to God" (ibid. 2:23).
They called Him "Hashem," as it says, "And we cried out to Hashem" (Deuteronomy 26:7), and He answered them, as it says, "Hashem heard our voice" (ibid. 26:8). They called Him "Yah" from Egypt, as it says, "From Egypt I called out to Yah, and He answered me in the expanse of Yah" (Psalms 81:6). Similarly, it says, "For what great nation is there that has a god so close to it as Hashem our God whenever we call upon Him?" (Deuteronomy 4:7).
Another meaning of "Mitzrayim" is "speaking of Egypt," as it says, "And they embittered their lives with hard labor, with mortar and with bricks" (Exodus 1:14). "In the expanse of Yah" means that God broadened His kindness to me, as it says, "The wings of a dove are sheathed with silver" (Psalms 68:14). Another meaning is in reference to David. When David left his brothers and they left him, all of Israel at that moment lifted their eyes to heaven, and David said, "A song of ascents.
I will lift my eyes to the mountains" (Psalms 121:1). The Holy Spirit answered him and said, "Do not let your foot slip; your Guardian does not slumber" (ibid. 3). In the expanse refers to how God broadened the way for David, and all of Israel followed him until they arrived at the Philistine camp, as it says, "And the Israelites returned from chasing the Philistines" (1 Samuel 17:53).