The departure of the Israelites from Egypt was not met with resistance. Instead, it brought an unexpected sense of relief and joy to their oppressors, driven entirely by overwhelming terror. The primary approach among commentators is that the Egyptian people were so battered by the series of plagues that they celebrated the Israelites leaving. A deep, paralyzing fear had fallen over the nation. They were convinced that if the Israelites remained in their land, every Egyptian would be completely wiped out. In their despair, they believed they were all going to die, making the exodus a moment of desperate salvation for Egypt itself.
Beyond the physical reaction of the nation, another layer exists within the spiritual realm [אלשיך]. In this view, the concept of Egypt refers not only to the physical country but to its spiritual guardian in heaven. This raises a question as to why this spiritual force allowed the Israelites to leave without a fight, only to attack them later at the Red Sea. The answer lies in the sheer magnitude of the final plague. The terror of the dying firstborns and the overwhelming fear of death struck the spiritual guardian just as it did the people below. Terrified by the destruction, this heavenly force was actually glad to see the Israelites go. It was only later, when the situation at the sea seemed to offer a fresh opportunity to harm them, that the spiritual guardian returned to wage war.