"the L-rd your G-d took you out of Egypt at night": Now did they leave at night? Did they not leave in the daytime, as it is written (Bamidbar 33:3) "On the morrow of the Pesach the children of Israel went out, etc."? We are hereby taught that the redemption began in the evening.
(Devarim 16:2) "And you shall slaughter a Pesach": Its slaughtering must be in the name of Pesach; otherwise, it is unfit.