Thou shall not offer the blood of my sacrifice with leaven,.... That is, not kill the passover, while there was any leaven in their houses; so the Targum of Jonathan; see Gill on Exo 23:18. neither shall the sacrifice of the feast of passover be left unto the morning; neither any of the flesh, nor of the fat of the passover lamb: if any were left, it was to be burnt, see Exo 12:10.