Jeremiah 32:40
And I will make an everlasting covenant with them, that I will not turn away from them, to do them good; but I will put my fear in their hearts, that they shall not depart from me. And I will make an everlasting covenant with them, that I will not turn away from them, to do them good; but I will put my fear in their hearts, that they shall not depart from me.
The everlasting covenant was given to Israel at the moment Jerusalem was about to fall to the Chaldeans, when its gates and palaces were to be burned and its people carried away captive under divine chastisement. Even with that destruction imminent, God's eternal purpose for Israel was still to be fulfilled.
Restoration is promised in the gathering of His people out of all the countries where He had driven them in anger and fury, bringing them back to their own place to dwell safely as His people. He will firmly plant them in the land with His whole heart and soul, and will rejoice over them to do them good. As surely as He brought great evil upon them, He will bring upon them all the good He has promised, reversing their captivity and causing fields to be bought again.
He will never turn away from doing good to His blood-bought people, but will give them one heart and one way to revere Him always for their good and for the good of their children after them. He will fix reverence in their hearts so that they shall never depart from Him.
That fear is holy reverence for the heavenly Father that keeps His honor and glory constantly in view. Joined with a realization of His great love, it produces gratitude, cheerful obedience, and firm, confident trust in Him. It brings the joy of Christ, expressed in blessing others.