Throughout the history of jurisprudence abortion has never been considered "murder" and even in the brief time it was criminalized it was always considered a much lesser crime. Moreover, the Bible specifically says it is not, in Exodus 21:22 in which it is clearly identified as a lesser offense. The assertion "abortion is murder" is merely excessive rhetoric much like "the Jonas Brothers are the most beautiful young men who ever lived."
Exodus 21:22 does not describe abortion but merely the unfortunate miscarriage of a baby resulting from an assault on a woman. These verses do not say that it is ok for a doctor to kill a baby when the woman has not suffered injury by a third party. Heck, the intentional killing of a baby is not alluded to in these verses at all. Lets read the verse in context.
Exodus 21:22-25
22"If men struggle with each other and strike a woman with child so that she gives birth prematurely, yet there is no injury, he shall surely be fined as the woman's husband may demand of him, and he shall pay as the judges decide.
23"But if there is any further injury, then you shall appoint as a penalty life for life,
24eye for eye, tooth for tooth, hand for hand, foot for foot,
25burn for burn, wound for wound, bruise for bruise.
The "lesser" offense relates to the woman not being injured, however, if the woman is injured then a stronger penalty is called for. These verses in no way condone the horrible practice of killing a baby.
Furthermore, killing a baby in the womb flies in the face of God's creation. God creates us and knows us in the womb. Those that condone abortion are destroying that which God has created.
Jeremiah 1:4-5
4Now the word of the LORD came to me saying,
5"Before I formed you in the womb I knew you,
Psalm 139:12-16
13For You formed my inward parts;
You wove me in my mother's womb.
14I will give thanks to You, for I am fearfully and wonderfully made;
Wonderful are Your works,
And my soul knows it very well.
15My frame was not hidden from You,
When I was made in secret,
And skillfully wrought in the depths of the earth;
16Your eyes have seen my unformed substance;
And in Your book were all written
The days that were ordained for me,
When as yet there was not one of them.
So, is abortion murder? It is in the eyes of the Lord.