Christopher Fisher explains why Psalms 139:16 does not mean what the Calvinists would claim. An excerpt:
The KJV translators correctly saw that King David’s subject did not stray. King David was still talking about fetology in verse 16. David is talking about being formed in the womb. God saw David developing in the womb, had a blueprint (book), and David’s fetal development followed that path. David’s point is not “fatalism”, but that “fetal development is not Ad Hoc”. Before David developed as a baby, that path had been designed by God.
To put this in perspective, in the preceding 3 verses David is clearly talking about how his body is designed during pregnancy. In the last verse, Calvinists believe David switches topics to talk about fatalism. This is a mistranslation. The entire passage is about fetal development.
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