The fear of the Lord is a reverential awe of his holiness, majesty, love, omnipotence and omniscience, which produces a dread of hindering our relationship with him by dishonoring or disobeying him.
Based on that definition, here are a couple of questions to help us assess where we are at in our fear of the Lord—First, how do you act and talk when there are no other mature Christians around? Secondly, what governs your home life or family life when no one else from the outside is looking on? Do you find it fairly easy to sin when no other Christian will know about it? Do you possess any desire to read the word or pray when no other human being will notice? Lastly, and by way of summary, what does your worship of Christ look like when it’s just you, your thoughts and the Lord?
Because the fear of the Lord is directly tied to accessing the knowledge of God and hating sin, there can be absolutely no sanctification apart from having it.