In the time of Moses, Egypt oppressed Israel terribly. God punished Egypt for this. In the book of Exodus, he is clearly shown as the true God. Despite this, God's people still turned to the same nation who oppressed them for help in times of crisis. They needed to be reminded of God's sovereignty.
1 Oracle sur l'Egypte.Voici, l'Eternel est monté sur une nuée rapide, il vient en Egypte; Et les idoles de l'Egypte tremblent devant lui, Et le cœur des Egyptiens tombe en défaillance.