The importance of God's spirit to our understanding Paul stated,
“But as it is written Eye hath not seen nor ear heard neither have entered into the heart of man, the things which God hath prepared for them that love him.
But God hath revealed them unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God.”
(1 Cor. 2:9,10 AV)
Sounds all-inclusive. Who would need to add to the Scriptures?