A covenant.... a promise from someone who doesn't break promises.
Jeremiah was told there is a new covenant coming.
"....I will put my law in their minds, and write it on their hearts. I will be their God and they will be my people." 31:33 and seen in Hebrews 8:7-12, 10:15-17
His Promise, Jesus' rescue.... 'We have confidence to enter the Most Holy Place by the blood of Jesus...' so ...'Let us not give up meeting together...' Hebrews 10:19-25
600 BC - Promise Given
30 AD - Promise Fulfilled
2020 AD - Promise enjoyed.
That's some promise.