The new covenant in Christ is radically different from the old one. The author quotes Jeremiah 31:31-34 to show a few things about it. First, the new covenant should not be a total surprise as God had long foretold that He would make a new covenant with His people (Hebrews 8:8; Jeremiah 31:31-34). Second, the word for new is kainos (Hebrews 8:8), meaning it is not only new in terms of the passage of time (for which the word neos would have been used, see Hebrews 12:24), but also new in quality.

The disappointing results associated with the old covenant were due to the sinful disobedience of the Israelite forefathers and their failure to be faithful to God according to the terms of the covenant. In the old covenant, the Lord placed His word before the people, and they often chose to reject it. But in the new covenant, God promised to ″put my laws in their minds and write them on their hearts″ (Hebrews 8:10). The Word would be internalised through the work of the Holy Spirit, of whom Jesus said, ″He will guide you into all the truth″ (John 16:13; ″[God's] word is truth″, John 17:17); and ″remind you of everything I have said to you″ (John 14:26). In the new covenant, Jesus gives the Holy Spirit to His disciples (John 20:22). God not only expects us to be faithful, but He will also give us the means to do so as we are filled with the Word (Colossians 3:16) and Spirit of Christ (Ephesians 5:18).

The result of such an infilling is that the person will know God and does not need to be taught or told by others; he will experience God first hand. No one will need to know God through the mediation of others, or relate to God by merely following others. Every person will know God, no matter who they are (″from the least of them to the greatest″, Hebrews 8:11). In this new covenant, God says ″I will be their God, and they will be my people″ (v. 10), having forgiven and forgotten their sins on the basis of the work of Christ on the cross (v. 12).

Thus, the old covenant is ″obsolete and outdated″ and will ″soon disappear″ (Hebrews 8:13). It is gēraskōn (outdated) and about to aphanismos (disappear). It would be foolish to hang on to the old after the new has come.