The first sign of a kosher animal is its split foot. The foot both touches the ground and separates us from the ground. It therefore alludes to the notion that in our involvement with the physical world, we must remain separate from it, aloof in our dealings with materiality. The fact that the foot must be split alludes to the notion that there must be an opening in this barrier: We must make sure that the light of holiness permeates even the most mundane aspects of creation, and make sure to retain Divine consciousness even when we are involved in the mundane aspects of our lives.
The other sign of kosher land animals is rumination. This alludes to the necessity of deliberating before engaging the mundane aspects of life. First, we must weigh our intentions, ensuring that they are solely toward elevating the world, purging them of any desire to simply indulge in sensuality for its own sake. Second, we must weigh the methods we employ in elevating the world, ensuring that they conform to the guidelines set forth in the Torah.1
The Torah specially states we should not cook the baby goat in its mother’s milk. Especially straighten the special bond between the mother and its child. Despite that clear mitsva the sages changed that in we should not eat any meat with milk (disrespecting the actual sentimental bond between mother and child by making it a general rule without the sentiment) in contradiction with the law that nothing should be add or change any words written by Moshe in the holy scriptures.