It is true that some patristic
comments and ancient
translations take the phrase
to mean "within you".
For a clear and instructive
discussion of the interpretations
and their history Fitzmyer, Luke
p.1161 discusses most of the issues.
He argues that the evidence favours
either "within your grasp"
or "amongst you".
There are other places in the NT which
do refer to inner experience, this one
probably does not.
David Mealand, University of Edinburgh
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.