קדש לי כל בכור פטר כל רחם בבני ישראל באדם ובבהמה לי הוא
The mitzvah of Pidyon HaBen, redeeming the firstborn, is directly connected to yetzias Mitzrayim, the Egyptian exodus. Hashem refers to the bechorim, first born: Li hu, “They are Mine.” Rashi explains that Hashem smote the Egyptian firstborn and spared their Jewish counterparts. He acquired the Jewish firstborn. The decree was solely directed towards the Egyptian firstborn; makas bechoros, the plague of the smiting of the firstborn, was the coupe de grace of the ten makkos, plagues, with which Hashem struck the Egyptians. What does it have to do with the Jews? Horav Shlomo Wolbe, zl, cites a Novoradok (Yeshivas Bais…