Using the Bible for it's own commentary on the Bible:
For this people's heart is waxed gross,
lest at any time they should see with their eyes,
For this people's heart is waxed gross,
and their ears are dull of hearing,
and their eyes they have closed;
lest at any time they should see with their eyes,
For the invisible things of him from the creation of the world
are clearly seen, being understood by the things that are made,
even his eternal power and Godhead; s
o that they are without excuse:
Romans 1:20
and hear with their ears,
While it is said,
To day
if ye will hear his voice, harden not your hearts,
Hebrews 3:15
and should understand with their heart,
Search the scriptures;
for in them ye think ye have eternal life:
and they are they which testify of me.
John 5:39
and should be converted, and I should heal them.
And from Jesus Christ, ....the first begotten of the dead, ....
Unto him that loved us,
and washed us from our sins in his own blood,...
Revelation 1:5
Matthew 13:15