'Sign' here means an indication, evidence or proof.
The King James Version is an old version of the Bible, with traditional, old-fashioned wording. This is the version which was found in the writer's church when he/she was a small child. At some point later, the church replaced these with copies of the New International Version, with more modern wording.
The writer knows the KJV wording by heart - this is evidence of the fact that he/she memorised the verses at an an early age.