Leviticus 7:21

Moreover, the soul that shall touch any unclean thing, as the uncleanness of man, or any unclean beast, or any abominable unclean thing, Cf chaps. 12-15, and eat of the flesh of the sacrifice of peace-offerings which pertain unto the Lord, even that soul shall be cut off from his people. The abomination spoken of here included all the unclean fishes, birds, and smaller mammals, and the defilement of unclean animals was confined to their carcasses, carrion being considered especially filthy. The Lord indicates here that He wants pure hands and pure hearts in His service. But to this day true sacrifices of thanksgiving and the paying of vows are acts well-pleasing to the Lord, if they are done in true faith and love toward Him, Psalms 50:14.