Isaiah 1:1, 10-20 and Genesis 15:1-6 and Hebrew 11:1-3, 8-16 and Luke 12:32-40
This set of readings gives us a great overview of the Biblical storyline, starting in Genesis, before Abram has been renamed Abraham. From that ancient story we get the three major monotheisms of today, the Abrahamic religions. And the theme here is sacrifices. Everyone knows God asked Abraham to sacrifice his son, but then replaced him with a lamb at the last minute. I'll deal with that more when it comes around, for now, keep in mind the stories of Abraham tell us what kind of God we will be dealing with.He is a God that makes promises. He says to leave where you are and go find the promised land, and He will give you progeny forever. These verses are sometimes used to differentiate the Muslim progeny from the Judaic, but I'm not going to cover that now.
Later, with Isaiah, we're being told all of that blood sacrifice stuff is wrong. We get that back in the 10 commandments too, but it seems to keep popping up. Archaeological evidence supports the fact that people continued to perform sacrifices and create idols. It can be hard to find, but the Bible tells us God's people did it too, despite the rules that said not to. Easier to find are passages like this, where they said not to sacrifice to other gods. They are usually mixed, like this one, with statements about having faith, and how the promises weren't always fulfilled, but progress keeps being made, and maybe the promises aren't fulfilled because you aren't listening to God.
Even if the Bible only had passages like these, the question of why they are needed would still be there. If you were going to make an instruction manual, then you would just start out in Genesis saying don't do sacrifices. But prophets and leaders do them, and seem to fare just fine. Other times, a little idolatry will get you immediately killed. This verse is telling people not to do blood sacrifices because quite clearly they have been doing them. Oddly, if you don't stop, God will “devour you by the sword”. I don't advocate spanking children because it makes it awfully difficult to explain to them later that they can't solve their problems by violence. Apparently God doesn't get this.
Then, we get to a letter to the Hebrews. This is another of disputed authorship. That dispute is not some modern revision either. It goes back as far as the 4th century. It is saying the important thing is faith, even though the promises have not been fulfilled. And now there is this new thing called heaven. The Old Testament talked about sheol, a place everyone went, somewhere underground. The Greeks had Hades and the underworld and this seems to have influenced the New Testament writers somewhat. In this letter we are told there is a heavenly city prepared for us. It's location, details of how it looks or what we'll do there, even how to get there are not forthcoming. Only vague directions about going “through Christ”.
In the book of Luke, a few more instructions are given. The controversial “sell your possessions” verse starts this off. Since almost no one has done this throughout history, it seems pointless for me to explain why I think it is bad advice. How does this even work after the first generation with people alive who said they knew Jesus? Would children just never acquire anything as they grow into adults? Aside from a few monastics, how does that work? I've been agreeable to the recent verses about not putting the accumulation of stuff ahead for friends, family and community, but this is unworkable.
Apparently you need some nice clothes and some lamps. And you should consider yourself “like” a slave. This verse is partially redeemed by the master who sits down and becomes the servant. But that master is still the master and could get up anytime.
I heard a story once of two African American women traveling on a train in America in the days when all the porters were black men. It was one of the first really good jobs they could get and it helped to bring descendants of slaves into the middle class. The story took place after these jobs had been around for a while. One of the women said, “We've made progress, but it will a great day when those black men are sitting having their drinks and the white men are the ones behind the counter and in the kitchen.” The other women said, “Yes, but it will be an even greater day when there is no counter and everyone is serving each other.”
But, I digress. The Luke passage ends with a couple verses that get repeated when someone claims to know the date of the “end of times”, when Jesus returns. These verses say we won't know that, we should be ready for it anytime. Again, I can almost redeem this if I think of it as always being at your best, always treat others well, keep your house clean and keep yourself in shape. It's just telling me to do those things for the wrong reason. This is where Christianity has been for two millennia now, waiting for that hour.
Mark chapter 13 goes on at length about the end times. Luke has softened it but they both may have been drawing from a common source that has been lost. This is sometimes called the “Q Source”. I'm not sure how much historic consensus still supports the Q theory, but you will hear it mentioned.
All of these passages are about having faith. They are about waiting for God to bring us somewhere or give us something. You don't get those things by doing sacrifices. You get them by reading the Bible, praying, and sharing it with others. The details of the promises change, but it's always something out of reach.