“And they shall not teach every man his neighbour, and every man his brother, saying, Know the Lord: for all shall know me, from the least to the greatest.”
King James Version (KJV)
8:11 And they who are under this covenant (though in other respects they will have need to teach each other to their lives' end, yet) shall not need to teach every one his brother, saying, Know the Lord; for they shall all know me - All real Christians. From the least to the greatest - In this order the saving knowledge of God ever did and ever will proceed; not first to the greatest, and then to the least. But the Lord shall save the tents, the poorest, of Judah first, that the glory of the house of David, the royal seed, and the glory of the inhabitants of Jerusalem, the nobles and the rich citizens, do not magnify themselves, #Zec 12:7|.
Heb 8:11 And they shall not teach every man . . . saying, Know the Lord. See Jer 31:34. Under the old covenant children were born into covenant relation. As they grew up they had to be taught of the Lord, or they would never know him. As a matter of fact, many did not learn to know him. For all shall know me, from the least to the greatest. But under the new covenant all must learn to know God and the Son whom he hath sent before they can enter the covenant. Every one must enter by faith in Christ, repentance of sin, and surrender to the will of God. Hence all members of the new covenant know God, "from the least to the greatest".