Thus saith the LORD against all mine evil neighbours, that touch the inheritance which I have caused My people Israel to inherit; “Behold, I will pluck them out of their land, and pluck out the house of Judah from among them.  And it shall come to pass, after that I have plucked them out I will return, and have compassion on them, and will bring them again, every man to his heritage, and every man to his land.  And it shall come to pass, if they will diligently learn the ways of My people, to swear by My name, ‘The LORD liveth;’ as they taught My people to swear by Baal; then shall they be built in the midst of My people.  But if they will not obey, I will utterly pluck up and destroy that nation,” saith the LORD.
Jeremiah 12:14-17

No one person, group, or nation can have peace with the LORD, unless and until they believe His word and obey His law.

What about mercy?  What about grace?

Reading the history of Israel/Judah they were disobedient to the LORD, again and again.  Yet, He had mercy on them and would free them from bondage to their enemies.  Sending the back to their land the LORD has given them.  What have they deserved?  To be forsaken by God, and leave them in bondage to their enemy.  What do they receive from God?  Grace.

The ones who will believe what God says about His Son Jesus, believing His who counsel of the word will at least have desire to live a life surrendered to the LORD as our Master.  If you do not desire to live a surrendered life to Him,  then you are apart from Him.