What part of God's Word is less the Word of God than another?

As one hears and believes the Word of God, it can only be heard, believed and followed as a whole.   

What part of God's Word is less the Word of God than another?  

Is Christ, the Word made flesh, divided?

Those who would believe one part of God’s Word in the living of the faith and overlook or reject others, do not so much submit their living to the Word of God, as they save and gratify the living of their own pleasures and fancies about what God would have them believe and live.  Such people submit themselves to Word and will of God only so far as it pleases them to do so. 

Surely the Lord Jesus Christ, the Word made flesh, described such buffet believers when He answered this question:

“‘Lord, will those who are saved be few?’

And he [Jesus] said to them, ‘Strive to enter through the narrow door. For many, I tell you, will seek to enter and will not be able.

When once the master of the house has risen and shut the door, and you begin to stand outside and to knock at the door, saying, ‘Lord, open to us,’

then he will answer you, ‘I do not know where you come from.’

Then you will begin to say, ‘We ate and drank in your presence, and you taught in our streets.’ But he will say, ‘I tell you, I do not know where you come from. Depart from me, all you workers of evil!’” Luke 13:23-27 (ESV)

Sanctify them in the truth; your word is truth.   John 17:17 (ESV)