TENDERNESS OF THE HEART AND THE FEAR OF GOD

1 NOW THE SPIRIT EXPRESSLY SAYS THAT IN LATTER TIMES SOME WILL DEPART FROM THE FAITH, GIVING HEED TO DECEIVING SPIRITS AND DOCTRINES OF DEMONS,
2 SPEAKING LIES IN HYPOCRISY, HAVING THEIR OWN CONSCIENCE SEARED WITH A HOT IRON."
1 Timothy 4:1,2 (NKJV)

One of the things that a believer should guide not to lose is the tenderness of his or her heart and the fear of God. Do not allow your heart to be seared or calloused!

Your conscience is the voice of your spirit man, the recreated human spirit, which should not be allowed to be calloused or seared. If you did allow your conscience to be calloused or seared, you would be permitted to commit sins freely without any remorse.
If you had been constantly disobeying or violating your conscience, it would get to a point that it becomes seared or calloused and given a way to any negative thing you may want to do—you would no longer be checked or restrained again by your conscience but be permitted to do whatever you want.

Your conscience is one of the functional parts of your spirit man, apart from the intuition and fellowship. It is usually not the Holy Spirit Who condemned when a believer missed it or committed a sin or did wrong, it is his or her conscience. Your conscience would make you lose your peace when you did anything wrong, not the Holy Spirit. When you see a believer committing sins or living in a sin and entrenched in it without any remorse, such a believer has wounded his conscience and the conscience has relented—given up and permitted him to do whatever he would want to do.

Note: some have allowed their hearts or spirits, the conscience, to be calloused or seared to the point that when they are committing a sin, doing a wrong or dirty thing, they would still be arguing and fighting as If they are doing the right thing. When such a person is confronted to be corrected in his or her sin, they would be arguing blindly and would not mind to quarrel with the person who is trying to talk sense to them: "HE WHO IS OFTEN REBUKED, AND HARDENS HIS NECK, WILL SUDDENLY BE DESTROYED, AND THAT WITHOUT REMEDY" (Proverbs 29:1 NKJV).

The journey usually starts from being disobedient and trying to justify the wrong things that are being done by the person, the believer—justifying their unwholesomeness, the uncleanness or corruption or disobedience (1 Samuel 15:13-23).
If corrections and efforts to bring back the believer to the right track are abortive, he or she would degenerate further and the tenderness of their heart or conscience would be lost. In such a state, It would always be hard or difficult to get such a believer convinced when they did anything wrong, because the tenderness of their heart or conscience is gone.
Further down the line, If nothing is done to correct or change the believer, he or she would be accommodated by demons—such a believer would begin to give heed to deceiving spirits and doctrines of demons—being taught by the ministers who are not of God (1 Timothy 4:1).
If it goes on, after a while, he or she would also begin to speak lies in hypocrisy—they would begin to act under a deceit (1 Timothy 4:2). They would begin to speak in line with what they are hearing, the hypocrisy they are hearing from the false teachers who are being led by the deceitful spirits.

Also, If the recalcitrancy persisted, the conscience would no longer prick him or her when they did wrong or about to do anything wrong—because the conscience that supposed to prick or check him or her is already silenced or seared and made inoperative, through the constant violation of it.
At this point, the fear of God would no longer be in the believer again, because the conscience has given up, permitting them to do whatever they wanted to do—the point of reverencing God or trembling at His Word would no longer be there (Isaiah 66:2).

Note: when a believer loses the tenderness of his or her heart or conscience, because it supposed not to be lost; the intimacy of such a believer would be totally lost.
This tenderness of the heart causes the reverential fear, palpitation, and constantly acknowledgement of God. Thus, when the tenderness is gone, all the attributes—reverential fear, palpitation and constant acknowledgement of God—mentioned here would all be gone.

In conclusion, one would notice that the degeneration of the believer in question is gradually done. The devil does not take hold of his victims at once, he does his work of possession gradually and systematically. It is always from one level of degeneration to another—such believers usually lost their grounds in the faith gradually!
The next point after these series or stages of degeneration is that such would depart from the faith (1 Timothy 4:1). Albeit, It my prayer that this would not be your portion in Jesus' name.
Therefore, endeavour to guide, protect and preserve, the tenderness of your heart.
Peace!