Exodus 23:19

Dam. The paschal victim must not be so young as to be still suckled. The Samaritan subjoins, "Because that would be like immolating an animal found dead, and the God of Jacob hates it." (Calmet) --- Some imagine that this law alludes to a superstitious custom of the pagans, (Spencer, Rit. ii. 8,) or it forbids eating animals while they are, as it were, all milk, not eight days old. (Rivet)