"When men strive together and hit a pregnant woman, so that her children come out, but there is no harm, the one who hit her shall surely be fined, as the woman's husband shall impose on him, and he shall pay as the judges determine. But if there is harm, then you shall pay life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burn for burn, wound for wound, stripe for stripe" (Exodus 21:22-25).
The two sides of the abortion debate treat the passage above in quite distinct ways. Firstly, we must recognize two cases involved in the passage: The first being that no harm was caused (Case 1), and the second, that harm was indeed caused (Case 2).
The pro-abortionist sees both cases as involving a miscarriage, with Case 1 having only the fetus as dying and with Case 2 having both the fetus and the mother as experiencing the same fate. It is argued that since only a monetary compensation is prescribed for the loss of the fetus, Scripture does not treat it as already possessing the status of a full human, unlike Case 2, when the "Lex Talionis" principle is enforced for the death of the mother:
"According to the interpretation reflected in most modern English translations of this law, miscarriage is involved in the basic situation described in v 22a as a common denominator of both Case A and Case B. The RSV, for example, translates: 'so that there is a miscarriage.' The 'ason mentioned in vv 22b and 23a can only refer then to the woman. Case A thus involves loss of the fetus only, and the penalty (v 22c) takes the form of monetary indemnification of the woman's husband according to a scale of assessment in which the determining factor is the age of the fetus. In Case B, in addition to the miscarriage the woman suffers 'ason, and the penalty clause (vv 23b-25), utilizing the talion formula, prescribes capital punishment, 'life for life,' if the woman dies. There is, according to this interpretation, a difference in kind in the penalties for destroying the fetus and for killing the woman, and the fact that a monetary settlement is prescribed for a miscarriage rather than a life being required as in the case of the woman's death means that the fetus was regarded in Israelite jurisprudence as mere property, not as a living person like the woman."
The anti-abortionist, on the other hand, does not see Case 1 as a miscarriage, but that the child was born unscathed, with the mother suffering only minor harm. This, according to the view, justifies the mere monetary compensation required. However, in Case 2, it is either the fetus or the mother, or both, that suffer death, and thus the "Lex Talionis" is applied, revealing Scripture's stand on the full humanity of the unborn fetus:
"Over against this exegesis stands the interpretation of Exod 21:22-25 widely endorsed in the anti-abortion movement. According to it, miscarriage is not involved in the basic situation described in v 22a. What comes forth is denoted by the plural of the regular word for child (yeled), and it is argued that there is no linguistic warrant for under- standing this as a miscarriage. Verse 22a describes the premature birth of a healthy child. The 'ason statement in vv 22b and 23a refers in each case to both the mother and the child. Case A involves only some minor harm to the mother, something less than is denoted by 'ason, and therefore a pecuniary penalty is sufficient. In Case B, the lex talionis applies whether the victim is the mother or the fetus singly or whether both are victims. The fetus is thus treated as a living person, just like the mother."
Meredith Kline, while agreeing with the anti-abortionist's view on the full humanity of the unborn fetus and the just imposition of the "Lex Talionis" in the event of its demise due to the agency of another, does not see any qualitative difference between the penalties imposed on Case 1 and Case 2 as described in the passage. In Case 1, the husband has much legal right to impose the "Lex Talionis" as he does to require monetary compensation:
"While accepting as sound the conclusion concerning the unborn child reached on this second interpretation, I would maintain that that conclusion must be set on a different exegetical base. By way now of developing such an exegesis, attention will first be given here to the penalties in the two apodoses. It will appear that even if it were granted that the first penalty has reference to a miscarriage and the second penalty to harm suffered by the woman, as the dominant interpretation suggests, it would still not follow that the penalty for the destruction of the fetus was different in kind or even in degree from the penalty for harming the woman.
The penalty clause for Case A reads in part: 'He shall be strictly penalized; whatever amount the husband of the woman demands of him he must pay' (v 22b). The verb 'ns denotes punishment.  This may take the form of a fine (cf. Deut 22:19), but possibly the verb refers to punishment in general, including physical punishment."
Further, he states:
"If the foregoing analysis is substantially correct, there are no essential differences between the penalties prescribed in Case A and Case B of the law in Exod 21:22-25. In both cases the penalty contemplates an offense involving death (as at least one possibility), and in both cases, where a death is involved the penalty may be understood as demanding a ransom for the offender's forfeited life. Therefore no matter whether one interprets the first or second penalty to have reference to a miscarriage, there is no difference in the treatment accorded the fetus and the woman. Either way the fetus is regarded as a living person, so that to be criminally responsible for the destruction of the fetus is to forfeit one's life."
Kline sees Case 1 as not stating that no death ensued, but that it is actually the mother who died, thereby negating the notion of the supposed relegation of Scripture of the fetus to the status of not fully human and therefore not meriting the imposition of the "Lex Talionis":
"It has been established above that when the protasis of Case A (v 22b) says there is no 'ason it cannot refer to both mother and fetus. The meaning of the term 'ason, as well as the location of the statement immediately after wys'w yldyh, favors a reference to the fetus. A calamitous loss involving serious injury or even death is denoted by 'ason. In the only other Biblical context where 'ason is found it describes the grievous calamity that Jacob fears might befall Benjamin on the journey to Egypt (Gen 42:4, 38; 44:29). The choice of this unusual word in Exod 21:22 (problematic if the reference were to injury or death of the woman, for which the more common terminology would then be expected) is readily explained if 'ason refers to the less everyday circumstance of the calamitous loss of offspring by violently induced miscarriage.
What indications there are point rather definitely and consistently, even if not with absolute conclusiveness, to the view that the mother is the victim in Case A (cf. 1 Sam 4:19-21) and the child in Case B. The sequence of victims in Exod 21:22 ff. then corresponds to that in the legislation in Exod 21:28 ff., which we have found to be similar in other important respects as well. In the law of the goring ox, the order of the victims is: the man or woman (v 29), a son or daughter (v 31), a male or female servant (v 32). In the law of the striking of the pregnant woman, the victims are in order (on our interpretation): the woman (v 22), the child (v 23), and (if we continue into vv 26-27, which are linked to the preceding law by the transitional talion formula) a male or female servant. Moreover, the treatment of the fetus (on our interpretation of v 23) corresponds to that of the son or daughter in v 31 in that the penalty in their case too is identical with the penalty already prescribed for an adult. It may be noted that in one of the Middle Assyrian laws of miscarriage the penalty for striking a woman, whether with non-fatal or fatal result for her, is mentioned first and then the penalty for the loss of the fetus."
"Case A envisages the death of a mother in giving birth prematurely to a live, uninjured child, and the law prescribes that the assailant must give for his forfeited life whatever the husband demands. In Case B the law requires that if the child suffers calamitous injury or death the penalty payment must be a just equivalent.
On this interpretation of Exod 21:22-25, it is of particular importance for the Biblical view of the nature of the fetus that the life-for-life formula is applied to the destruction of a fetus, with no qualification as to how young the fetus might be. The fetus, at any stage of development, is in the eyes of this law a living being, for life (nepes) is attributed to it. To be sure, the life-for-life formula is also used in the case of the death of animals (Lev 24:18), so that this formula by itself does not establish that the referent is a human being. But if it is the fetus of a human mother that is identified by the life-for-life formula as a living being, there can be no question that this living being is a living human being. Significantly, the part of the talion formula specifying injuries to eye and tooth and the like is not applied to animals. Only in the case of human beings do these features take on the value that merits legal redress. And surely the living fetus in view when the talion formula mentions the loss of life (v 23c) must be identified with the human child referred to in the talion formula as suffering the loss of eye or tooth (vv 24, 25). Consistently in the relevant data of Scripture a continuum of identity is evident between the fetus and the person subsequently born. And Exod 21:22-25 makes clear that this prenatal human being is to be regarded as a separate and distinct human life."
Finally, Kline offers a damning critique of the Zeitgeist as it pertains to the unborn child and the wanton disregard for its humanity, citing the moral superiority of even the basest pagan of ancient times as compared to the modern sophisticate:
"As we observed at the outset, induced abortion was so abhorrent to the Israelite mind that it was not necessary to have a specific prohibition dealing with it in the Mosaic law. The Middle Assyrian laws attest to an abhorrence that was felt for this crime even in the midst of the heathendom around Israel, lacking though it did the illumination of special revelation. For in those laws a woman guilty of abortion was condemned to be impaled on stakes. Even if she managed to lose her own life in producing the abortion, she was still to be impaled and hung up in shame as an expression of the community's repudiation of such an abomination. It is hard to imagine a more damning commentary on what is taking place in enlightened America today than that provided by this legal witness out of the conscience of benighted ancient paganism!"
Source: LEX TALIONIS AND THE HUMAN FETUS by Meredith G. Kline