Some contend that the Bible approaches the subject of abortion in Exodus
(22) when two brawling men accidentally strike a pregnant woman. If the woman is injured, the inadvertent assailant gets punished, receiving the very same wound he caused the woman: an eye for an eye, a tooth for a tooth. If the woman dies, then it is a life for a life and the man who caused the injury dies. But if the woman miscarries, then the assailant just pays a fine.
So, an injury caused to the woman is one thing. The injury to her fetus is not viewed the same way. This same biblical passage does not say that the fetus is a human being like the injured women or like you or me. If the fetus were considered human, the punishment for injuring the fetus would be the same punishment as that for injuring the pregnant woman.
The book of Exodus warns us to take care around a pregnant woman. Cause her to miscarry, it costs money. Cause her to die, and the penalty is death. The Bible extends a full measure of legal protection to a pregnant woman, a fullness of rights and protection that is not extended to the fetus.
But these verses simply discuss the fetus; they are not about abortion. They do not permit, proscribe, or prohibit abortion. They consider an accidental miscarriage but do not describe the willful termination of a pregnancy. And what if a woman wants to end her pregnancy? Let's say the fetus endangers her life or her physical or mental health. If she decides on abortion, the Bible is silent.
Here is an article from John Piper on this Exodus 21 passage used by pro-choice advocates.