Leviticus 22:28

And whether it be cow or ewe, ye shall not kill it and her young both in one day.

The law forbids killing a cow or a ewe together with its young on the same day. That restraint curbs cruelty and guards against inflicting needless suffering on animals. Slaughter done wholesale tends to breed more cruelty and heartlessness than killing one animal at a time.

The refusal to allow mother and young to be offered together pictures the Father giving up His Son, their enforced separation representing the Son taken out of the Father's care by wicked men. The cries of the young lamb when torn from its mother picture Christ, the Lamb led to the slaughter, crying out in anguish. The command thus reveals God's love in not sparing His own Son but delivering Him up for humanity.