Contradiction with Jeremiah 31:33
This verse speaks of God's law being placed in the hearts and minds of people, contrasting with the idea of physically binding instructions as stated in Proverbs 6:21.
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 Matthew 5:17
Jesus speaks of fulfilling the law rather than keeping commands and instructions tied to one's heart and neck as described in Proverbs 6:21.
Matthew 5:17: Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil.
Contradiction with Hebrews 8:10
Similar to Jeremiah 31:33, this verse states that God will put His laws within people's hearts, indicating an internal, rather than external, observance that contrasts with Proverbs 6:21.
Hebrews 8:10: For this [is] the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people: [put: Gr. give] [in: or, upon]
Contradiction with 1 John 5:3
This verse explains that the commandments are not burdensome, which can contradict with the interpretation of physically binding them as described in Proverbs 6:21.
1 John 5:3: For this is the love of God, that we keep his commandments: and his commandments are not grievous.