“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”- Jeremiah 32:40

These covenanted ones may be known by certain marks and evidences. It is most important that we should know that we ourselves belong to them. They are a people, according to the text, to whom God is doing good. Friend, do you perceive that He is doing good to you? Has the Lord dealt graciously with you? Has He appeared to you, and said, “I have loved thee with an everlasting love: therefore with lovingkindness have I drawn thee”? Do all things work together for good for you? I mean, for your spiritual good? your lasting good? Have you received the greatest good by the renewal of the Holy Spirit? Has He given Christ to you? Has He made you hate evil and cleave to that which is good? If these good gifts have been bestowed on you, He has done you good; for these gifts are the outcome of the covenant and are sure guarantees that it stands fast between God and your soul.

These people are known by having the fear of God in their hearts. Judge ye, whether it be so in your own case. This is the covenant promise-“I will put My fear in their hearts.” Do you fear the Lord? Do you reverence Jehovah, our God? Do you desire to please the Lord? Do you please Him? Do you desire to be like Him? Are you like Him in some humble degree? Do you feel ashamed when you see how sadly you come short; and does this make you hunger and thirst after righteousness? Is the gracious presence of God your heaven below? Is it all the heaven you desire above? If so, this fear of God in your heart is the seal of the covenant to you. Towards you God has thoughts of love which shall never change. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2108.cfm