Numbers 5:11-31 is the account of abortion as a trial by ordeal for an Unfaithful Wife, proof being the aborted fetus. Part of ancient Mosaic Law given to Moses by JHVH. JEHOVAH IS A PRO ABORT. Jews knew about and practiced abortion. This is the law about abortion Jesus followed.
Quote from Judaism 101: Jewish law not only permits, but in some circumstances requires abortion. Where the mother's life is in jeopardy because of the unborn child, abortion is mandatory.
An unborn child has the status of "potential human life" until the majority of the body has emerged from the mother. Potential human life is valuable, and may not be terminated casually, but it does not have as much value as a life in existence. The Talmud makes no bones about this: it says quite bluntly that if the fetus threatens the life of the mother, you cut it up within her body and remove it limb by limb if necessary, because its life is not as valuable as hers. But once the greater part of the body has emerged, you cannot take its life to save the mother's, because you cannot choose between one human life and another. Mishnah Oholot 7:6.
Rambam, the highly-regarded medieval authority on Jewish law, describes a fetus that puts the mother's life at risk as a "rodef" (literally, a pursuer) under the traditional Jewish law of self-defense, which allow you to kill a person who endangers your life, and even requires others to help you where they can do so safely. (Mishneh Torah, Murderer and the Preservation of Life 1:9) The concept of rodef would apply even if the fetus were considered a human life, though the Mishnah passage above makes it clear that the fetus is not considered a human life until it is more than halfway born. Rambam's discussion of the concept of rodef in general indicates that lesser means should be used if a rodef can be stopped without killing, but when a fetus endangers the life of the mother, there are rarely lesser means that can prevent the harm. See the Rambam's laws of the pursuer at A List of the 613 Mitzvot (Commandments), 265 and 266.
Where does Judaism get the idea that a fetus is not equivalent to a human life? Jewish sources usually reference Exodus 21:22, which says that if men are fighting and they strike a woman and "yatz'u y'ladeha" (literally, her child goes out) but no harm happens, the men pay an appropriate fine, but if harm happens the men pay life for life, eye for eye tooth for tooth, etc. Now, Christianity typically understands this passage as involving merely a harmless early birth, but Judaism has always understood "yatz'u y'ladeha" as a euphemism for a miscarriage. If this incident merely caused an early birth with no harm, why would there be a fine? And if the death of the unborn were equivalent to the death of the living, why is the penalty merely a fine rather than life-for-life as the very next verse requires?
Talmud Bava Kamma 48b-49a discusses how to assess the value of damages when "yatz'u y'ladeha", and the entire discussion clearly understands that the child is not living. Ancient Jewish sources take this understanding much farther. In considering whether the execution of a theoretical pregnant woman should be delayed until after she gives birth, the Mishnah concludes that execution should only be delayed if she is already in labor. The Gemara elaborates that the plain reading is that before labor, "gufa hee" (it is her body!), citing Ex. 21:22. The Gemara goes on to reject any notion that the fetus is the property of the husband, thus executing the pregnant woman does not take away his property. Why should her execution be delayed if she is in labor? The Gemara explains, once the fetus is "uprooted," it is a different body from her! (see Talmud Arakhin 7a:11-15)