C:2Pe 1:20

∞ 2Pe 1:20 Knowing this first, that no prophecy of the scripture is of any private interpretation. 2Pe 1:21 For the prophecy came not in old time by the will of man: but holy men of God spake [as they were] moved by the Holy Ghost.

The interpretation of scripture is given to the interpreter by the same Spirit that gave the prophecy to the authors. The interpreter is 'moved' by the Holy Ghost as he studies and meditates on the Word of God. He is moved by the Holy Spirit to correlate the scripture with scripture.