Contradiction with John 1:18
This verse states that no man has seen God at any time, which contrasts with Deuteronomy 4:33, where it is suggested that God spoke to people directly.
John 1:18: No man hath seen God at any time; the only begotten Son, which is in the bosom of the Father, he hath declared [him].
Contradiction with Exodus 33:20
This verse mentions that no one can see God and live, contradicting the implication in Deuteronomy 4:33 that people heard God speaking directly.
Exodus 33:20: And he said, Thou canst not see my face: for there shall no man see me, and live.
Contradiction with 1 Timothy 6:16
It says God dwells in unapproachable light and no one has seen or can see Him, conflicting with the direct communication with God mentioned in Deuteronomy 4:33.
1 Timothy 6:16: Who only hath immortality, dwelling in the light which no man can approach unto; whom no man hath seen, nor can see: to whom [be] honour and power everlasting. Amen.
Contradiction with Numbers 12:6-8
These verses describe God speaking directly to Moses in a clear form, which contradicts the general implication in Deuteronomy 4:33 that hearing God's voice directly is a unique event.
Numbers 12:6-8: And he said, Hear now my words: If there be a prophet among you, [I] the LORD will make myself known unto him in a vision, [and] will speak unto him in a dream.