Realignment in History
The Tanakh tells of friends of God maybe as far back as the progenitor of mankind ("Adam"), certainly including (among many others) Hebrew progenitors Abraham, Isaac and Jacob (aka "Israel", from whom they claimed to derive their tribal name), and also non-Hebrews such as Melek-Zedek ("Melchizedech") and Ruth.
The Tanakh is the collection of ancient Hebrew texts also known as "The Hebrew Bible" or "The Old Testament".
The "Hebrews", also called "Israelites", were the population of ancient Israel.
"Jews" designates either all Hebrews or, more narrowly and etymologically (as in The Gospel According to John), only folk descended from the tribe of Judah or from inhabitants of Judea, the part of ancient Israel settled by Judah and including Jerusalem. This site prefers the narrower sense.
"Israel", on this page and elsewhere in this site, usually designates ancient Israel. Any mention of modern Israel will be explicit about that.
The ancient Hebrews called their god "Yahweh" (sometimes rendered "Jehovah"). Maybe they initially regarded him as merely one god among others, but later they certainly regarded him as the only god worthy of the name, and eventually as the only real god.
Ancient Israel (a nation like no other) and Christianoidity (a social movement like no other) have many implausible explanations and one obvious one, which is that they have been God's vehicles for saving humanity.
How far what I infer here from the Tanakh would be apparent to an earnest thinker with no prior awareness of the New Testament, I cannot say. Some see the wicked predisposition of all humans, and the need for God's realigning grace, as a distinctively New Testament doctrine. I think it implicit in at least parts of the Tanakh. But the question is not important here, for we have the New Testament and subsequent history.
The Tanakh is too bloodthirsty to be taken seriously.
The Law of Moses prescribed aggression, but established no precedent for aggression. Moses deplored aggression, but as it would occur anyway he stipulated a relatively mild form for it. The notorious "eye for an eye" was explicitly directed against even more severe retaliation. (Similarly, later, the prophet Samuel influenced the Israelites' choice of monarch after warning them against monarchy.)
"Because of their hardness of heart Moses wrote them that commandment."
Matthew 19:8. I think this applies to the whole law of Moses.
Back to God turns his foes into friends.