God's new promise is available Now

Read Jeremiah 31.

There are several metaphors used to describe God's the relationship with His people.
1. As a Father (v.9)
He disciplined them because of their disobedience.  But like a faithful parent, He did this in order to better prepare them as a nation for their future.  Nothing would change the fact of His commitment to them.
"I have loved you with an everlasting love; therefore I have continued my faithfulness to you." (v.3)
"There is hope for your future." (v.17)

2. As a Shepherd (v.10)
Because they belonged to Him, God promised to gather them as His flock.  He will care for them, feed them and protect them.

3. As a Redeemer (v.11)
His deliverance of them from the hands of the enemy is compared to paying a ransom.  The basis of the turn in their experience with God depended upon their repentance.  With grief and shame, their hearts cried out for God's mercy and forgiveness. (vv.18-20)  He would restore them to their land and bless them.

But there is much more ahead for Israel.  Three times we read, "Behold, the days are coming."  Here, God makes a future promise of a new covenant with Israel.  The results of this covenant for the Jews in verses 33-34 will be:
-God's law will be within them, on their hearts.
-They will all know the LORD.
-Their sins will be forgiven and remembered no more.
This obviously is a prophecy that remains unfulfilled in Israel.  However, as "the time of the Gentiles" came and were grafted into God's plan of redemption, all may enjoy the benefits of the new covenant (Romans 9-11).

At His last supper with His disciples, Jesus took the cup and said, "This cup is the new covenant in my blood.  Do this, as often as you drink it, in remembrance of me."  Forgiveness of sin is available to all who turn to Him for mercy.