The Messianic age is a promise—Yirmiyahu (Jeremiah) 31:26-34:
26) “Behold days are coming, says the Lord, and I will sow the house of Israel and the house of Judah with seed of man and seed of beasts.
27) “And it shall be, as I have watched over them to uproot and to break down, to demolish and to destroy and to afflict, SO WILL I WATCH OVER THEM TO BUILD AND TO PLANT, says the Lord.
28) “In those days, they shall no longer say, ‘Fathers have eaten unripe grapes, and the teeth of the children shall be set on edge.’
29) “But each man shall die for his iniquity; whoever eats the unripe grapes [false teachings/idol worship]- his teeth shall be set on edge.
30) “BEHOLD, DAYS ARE COMING, SAYS THE LORD, and I will form a covenant with the house of Israel and with the house of Judah, A NEW COVENANT.
31) “Not like the covenant that I formed with their forefathers on the day I took them by the hand to take them out of the land of Egypt, that they broke My covenant, although I was a lord over them, says the Lord.
32) “For this is the covenant that I will form with the house of Israel after those days, says the Lord: I WILL PLACE MY LAW IN THEIR MIDST AND I WILL INSCRIBE IT UPON THEIR HEARTS, and I will be their God and they shall be My people.
33) “And no longer shall one teach his neighbor or [shall] one [teach] his brother, saying, ‘Know the Lord,’ for THEY SHALL ALL KNOW ME [they will not be susceptible to false teachings] from their smallest to their greatest, says the Lord, for I will forgive their iniquity and their sin I will no longer remember.
34) “So said the Lord, Who gives the sun to illuminate by day, the laws of the moon and the stars to illuminate at night, Who stirs up the sea and its waves roar, the Lord of Hosts is His name.
35) “If these laws depart from before Me, says the Lord, so will the seed of Israel cease being a nation before Me for all time.
36) “So said the Lord: If the heavens above will be measured and the foundations of the earth below will be fathomed, I too will reject all the seed of Israel because of all they did, says the Lord.
37) “Behold days are coming, says the Lord, AND THE CITY SHALL BE BUILT TO THE LORD, from the tower of Hananel until the gate of the corner.
38) “And the measuring line shall go out further opposite it upon the hill of Gareb, and it shall turn to Goah.
39) “And the whole valley of the dead bodies and the ash and all the fields until the Kidron Valley, until the corner of the Horse Gate to the east, shall be holy to the Lord; IT SHALL NEVER AGAIN BE UPROOTED OR TORN DOWN FOREVER.”