Clamped the umbilical
The umbilical cord is what keeps a baby alive while he is in the mother’s womb.
This is used as an analogy. Abu Nurah was “clamped” or attached to his prior beliefs which really weren’t his personal beliefs as they are spewed out by the media and society (movies, news, papers, magazines, tv, etc) and therefore, basically forcing to think how they want you to.
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