Exodus 23:18

Thou shall not offer the blood of my sacrifice with leavened bread,.... This belongs to the feast of the passover; for, as all the Jewish writers agree, this sacrifice is the sacrifice of the passover, as it is sometimes called, see Exodus 12:27 now when the paschal lamb was killed, and its blood shed, and its flesh eaten, there was to be no leaven along with it; it was to be eaten with unleavened bread, and there was to be no leaven in their houses at this time; nay, it was not to be slain until all was removed: this was the first thing the Jews did, as soon as the fourteenth day was come, to search for leaven, remove and burn it; and this sense of the law is confirmed by the Targum of Jonathan, which is,

"not a man shall slay, while there is leaven in your houses, the sacrifice of my passover;''

and to the same purpose is the note of Jarchi:

neither shall the fat of my sacrifice remain until the morning; and indeed no part of the passover lamb was to remain until the morning, what did was to be burnt with fire, Exodus 12:10 the Targum of Jonathan is,

"neither shall there remain without the altar the fat of the sacrifice of my passover until the morning, nor of the flesh which ye ate in the evening;''

and so Jarchi interprets it of its not remaining without the altar.