The flakes of his flesh are joined together. They are firm on him. They can't be moved.
KJV
The flakes of his flesh are joined together: they are firm in themselves; they cannot be moved.
Commentary
Commentary
The flakes of his flesh are joined together,.... The muscles of his hefty are not flaccid and flabby, but solid and firmly compacted;
they are firm in themselves; they cannot be moved; that is, not very easily, not without a large sharp cutting knife, and that used with much strength.
Commentary
Commentary