Parshas Bo

(The Segulah of Learning Zera Shimshon)

The dogs were silent as Klal Yisroel left Mitzrayim. This in it of itself was a neis, but the unnatural silence was also a sign. It was sign that Bnei Yisroel had been forgiven for their sins and were worthy of this redemption.

The Medrash in Shemos Rabba (1:35) tells us that Moshe was curious regarding Klal Yisroel's sin. He was curious as to what they could have done to be sentenced to this forced labor. When he realized that Dassan and Aveiram found out who killed the Mitzri through lashon hara, he said, "This is a nation who speaks lashon hara. How will they ever be redeemed?"

The Gemara in Makkos (23a) writes that anyone who speaks lashon hara deserves to be thrown to the dogs.

The fact that the dogs were silent when Bnei Yisroel were leaving Mitzrayim shows that they did teshuva; they were no longer speaking lashon hara. Thus, they merited this redemption.

Source: Zera Shimshon Parshas Bo