Why dont people who claim to use christianity in tell me where in the bible does it say abortion is murder?

They like to point to the Bible to say God is against abortion and call it murder but where does it say abortion is murder? And the 10 commandments says thou shall not murder, it does not say what constitutes murder, so please tell me what it is, because otherwise God gave man the wisdom and freedom to decide for themselves that's outside the 10 commandments and to define what laws they want to enforce on how they interpret the 10 commandments and whatever you think murder is, legally abortion is not and the Bible doesn't say thou shall not commit abortion.

Why dont people who claim to use christianity in tell me where in the bible does it say abortion is murder?
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