Contradiction with Jeremiah 17:9
Suggests the heart is deceitful and wicked, contrasting with Deuteronomy 30:11 which implies accessibility and clarity of God's commandments.
Jeremiah 17:9: The heart [is] deceitful above all [things], and desperately wicked: who can know it?
Contradiction with Romans 7:18
Indicates inability to do good on one's own, conflicting with the notion in Deuteronomy 30:11 that the commandment is not too hard to accomplish.
Romans 7:18: For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but [how] to perform that which is good I find not.
Contradiction with John 8:43
Implies that understanding and following God's word might require more than just accessibility, unlike Deuteronomy 30:11 which states the commandment is readily knowable.
John 8:43: Why do ye not understand my speech? [even] because ye cannot hear my word.
Contradiction with 1 Corinthians 2:14
Says that natural man does not accept God's things, opposing Deuteronomy 30:11's idea of the commandment being within easy reach for understanding.
1 Corinthians 2:14: But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know [them], because they are spiritually discerned.