Contradiction with Jeremiah 31:33
Jeremiah establishes the idea of God writing laws in the minds and hearts of people, but Hebrews 10:15 suggests the Holy Spirit is the one witnessing this action, which may create confusion about the role of the Holy Spirit versus the direct action of God.
Jeremiah 31:33: But this [shall be] the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people.
Contradiction with Galatians 3:19
Galatians notes the law was ordained by angels through a mediator, contradicting Hebrews 10:15 which speaks of the Holy Spirit directly witnessing to us about the new covenant.
Galatians 3:19: Wherefore then [serveth] the law? It was added because of transgressions, till the seed should come to whom the promise was made; [and it was] ordained by angels in the hand of a mediator.
Contradiction with 1 Corinthians 2:14
This verse indicates that the natural man cannot receive the things of the spirit, potentially contradicting Hebrews 10:15’s assertion of the Spirit's direct witness to everyone.
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.
Contradiction with John 5:39
Jesus speaks of people searching the Scriptures thinking they have eternal life, which seems to contradict Hebrews 10:15’s emphasis on the Spirit bearing witness to the new covenant rather than the Scriptures themselves providing life.
John 5:39: Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.