Sacrificing to various Gods was a practice common to many civilizations long before Moses came along. Apparently sacrifice was the only way to appease God, no matter whose God it was. And these Gods needed plenty of appeasing. Pretty much everything you did, good or bad, required some sort of sacrifice. Besides that, there were numerous festivals literally built around ritual sacrifice. I won’t go into all the details but if you really want to know about it I recommend you read these two books.
For the record, sacrifice requires you give up something prized or of value in order to get something of higher value. What they gave up were things like sheep, cattle, oxen and, in some cultures, the first born child. What they got back was a happy God.
In a way it makes perfect sense from an ancient man’s point of view. These people were accustomed to having a powerful ruler over them. If you wanted something from him, of course you’d have to pay for it, and likewise, if you did something wrong you’d have to pay for that too. It’s only natural that if you wanted something from God, the biggest ruler of them all, you’d have to pay for it. The concept of a loving God who wants nothing more than to bestow all the fruits of the kingdom on you would have to wait until Jesus came along.1
Moses wanted to make sure his people did their sacrifices in the right way and with plenty of respect since, after all, their God was the best God, right? So he laid out very strict rules about how and what to sacrifice.
Regardless of what the sacrifice was for, there was one thing you could count on; lots of killing and plenty of blood. Depending on how wealthy you were, oxen, cattle and lambs were all fair game. For poor people it was doves and grain. And you couldn’t offer up just any cow or lamb in the field either; it had to be a spotless male without blemish. In other words, you had to give up your best to God.
They didn’t just kill it either. They’d cut it up, gut it, drain the blood and wave the various parts around the altar. Very often, burning the various parts was part of the ritual because God liked the smell. I guess God likes a good barbecue as much as anyone. He loved the smell of burning flesh.
It’s hard to imagine how messy this would be when they really got going. When you consider how many people there were and all the things that required sacrifice it would have had to have been a non-stop operation.
I mention this not to gross you out, but to show how established the notion of sacrifice, killing and blood were ingrained in the mindset of the people of the time. Particularly the Hebrews. Fifteen hundred years down the road this premise would become the cornerstone of the Christian religion.
This notion of not being good enough and needing to sacrifice in one way or another to become worthy is, unfortunately, still in the mindset of a huge number of people today.
1] The Good News.