Upon what did the counselor base his counsel to Rob?

The counselor likely based his counsel to Rob on a combination of factors. However, the most foundational basis for a counselor in a Christian context would typically be the Bible, as it is often considered the ultimate source of wisdom and guidance. Additionally, Rob's doubt and Rob's testimony could provide context for the counselor's advice, along with his experience in dealing with similar situations. Ultimately, the specific answer might depend on the context of the discussion, but the Bible is often emphasized as the primary source in such scenarios.

choose the best option

The best option would be the Bible. This is generally the primary source of counsel in a Christian context.