The answer is: Blood

Gen 9:4 - An early prohibition, re-affirmed in Lev 7:26.

After the Great Flood, Noah and his family encountered a dramatically altered world, and God's command to them included something surprising: a dietary restriction concerning blood. This intriguing command can be seen to emphasize the sanctity of life. In Genesis 9:4, God tells Noah, "You must not eat meat that has its lifeblood still in it." This isn't just a random rule; it's a clue to appreciating the life spirit found in every creature.

Now, let’s explore the deeper implications. Blood in the biblical context is often linked to the essence of life. Removing blood from meals was perhaps a way of reminding humanity not only of the value of animal life but also of their covenantal relationship with God. It's fascinating to note this echoes throughout scriptures – much later in Leviticus 7:26, the prohibition re-emerges, signifying its importance through the ages.

Interestingly, many ancient cultures also held similar beliefs about blood, reflecting a universal understanding of its sacred nature. Also, did you know that some argue this prohibition laid the groundwork for practices observed in kosher dietary laws? It seems that from the very beginnings of human civilizational narratives, there's an essential thread connecting our existence to ethical eating and grateful stewardship of life. So, next time you enjoy a meal, remember the echoes of Noah, reverberating through these age-old dietary rules!