Issues in the Interpretation of Prophecy Chapter 7 Special Literary Forms, Virkler's Hermeneutics pg 171

Interpretation must begin with Historical-cultural, Contextual, Lexical-syntactical and Theological analyses as other types.

Deeper Sense
A meaning intended by God but not necessarily by the author

In Isa 7:14 Isaiah had no concept of the virgin birth vs

In Isa 7:14 Isaiah did understand all he wrote, vs

In Isa 7:14 Isaiah did understand, but perhaps not all of the implications were understood. (Note that authors today often do not understand all their own implications, let alone when God is inspiring the pen!)