Hello there,
What I’d first like to do is to second what “JamalChristophr” brought up. As human beings, limited in our understanding of all things (including morality), we really have no right to be questioning the Creator both of the universe, and of morality as to what is good, and what isn’t. However, I suspect that you would like to see this question addressed through what is perhaps a more Western, or modernist lens. I will thus attempt to do that.
To begin with, we must recognize that God’s morals are absolute, and unchanging, and we must acknowledge that the crimes for which these punishments are prescribed remain immoral to this day. However, to a modern person, it would appear to be the case that the punishment does not fit the crime. I would say two things to this; firstly, one of the overarching theological themes of the Old Testament is the necessity of absolute obedience to God’s commandments, an obedience whose absence often leaves the ancient Israelites in hot water. What I believe God was seeking to accomplish in “laying down the law” in the Old Testament was to establish a base upon which further goals could be established with respect to the salvation of all of mankind. What we see in the Old Testament is that God first presented us with a very strict, and very righteous framework under which we could live, which failed due to our sinful nature. Secondly, the other point that I’d raise is the fact that violations of the Law at the time when Mosaic Law was first authored (assuming a traditional view of authorship, which I’ll not get into here) were more… immediate, one could perhaps say. What I’m struggling to describe with one word is the idea that God was more evident, and more immediate to people at that time, and that as such, transgressions against the Law were more evidently blasphemous, and egregious when viewed in the social context of the time. When Moses received the Ten Commandments on Mount Sinai, God literally handed them to him. God had led the Israelites through the desert to Israel. Many Israelis had witnessed the Lord at a deeply personal level, and knew for a fact that He existed. In my opinion, this means that for someone to have broken God’s commandments, especially in the context under which the Law was given, would have been incomprehensibly blasphemous, and thus more deserving of punishment.
To contrast with this, the new Covenant (open to both Jews, and Gentiles alike) has the appearance of being more lenient on law breakers. The lens of the immediacy through which we view the law breaking in the Old Testament is the lens through which I also view the reasoning behind the more relaxed law given in the New Testament. Christians are freed from many of the more difficult aspects of Jewish Law (both in terms of the punishment, and the crime) for two main reasons; 1) We are all redeemed by way of the grace of Our Lord and Saviour, Jesus Christ; and 2) The Gentiles had never known the Israeli God, and thus could not be expected to follow the Law as fervently as the Jewish population, especially given the influence of very Orthodox groups (such as the Pharisees) that was present at the time of Jesus.
I’d like to conclude with a few things. First of all, even if you don’t agree with my reasoning in terms of punishments, know one thing. The God of the Old Testament is the same God that we find in the New Testament; more than anything, he desires to love us, for we are his Creation. This is made evident when God first tells us to love our neighbour as we’d love ourselves, a first appearance which happens not in the New Testament, but in Leviticus 19:18. In line with this, available Rabbinical commentaries tell us that capital punishment was not in fact a common occurrence in Jewish culture, despite the bloodlust seemingly present in the pentateuch. Rabbi Akiva, who was a prominent Rabbi around the turn of the millenium, tells us that a court was considered to be deadly if it had one capital punishment case every seventy years. So once again, God’s grace always took primary consideration, and the death penalty was not a choice that was taken lightly. I hope that this wasn’t too much of a slog for you, and that I answered some of your questions. Have a blessed day!