Fear of the Lord
We can begin by saying what it is not: Pope Benedict XVI in his General Audience of 8 June 2005 taught: "It is not fear and terror that are suggested by this word, but serious and sincere respect which is the fruit of love, a genuine and active attachment to God the Liberator." Hence the 'fear' we speak of is not a servile terror of the servant for a dread and cruel Master; it is not even the fear of terrible punishment which is an imperfect kind of fear. Rather, we speak of the rightful reverence for God that is born of love, and St John says that "perfect love casts out fear" (1 Jn 4:18). The Conferences of the Desert Father John Cassian, explain it thus:
"Whoever then has been established in this perfect love is sure to mount by a higher stage to that still more sublime fear belonging to love, which is the outcome of no dread of punishment or greed of reward, but of the greatest love; whereby a son fears with earnest affection a most indulgent father, or a brother fears his brother, a friend his friend, or a wife her husband, while there is no dread of his blows or reproaches, but only of a slight injury to his love, and while in every word as well as act there is ever care taken by anxious affection lest the warmth of his love should cool in the very slightest degree towards the object of it."
Incidentally, it is also in this context that Ephesians 5:33 speaks of the reverence of a wife for her husband and vice-versa. This reverence is born of love, a concern to please the beloved and fear of hurting the Other. We hear it often enough in romantic movies when one says to the other: "The last thing I ever wanted to do is to hurt you" and of course this said after the hurt, lies, deception has been inflicted! This is often because the person may have acted out of fear, in the more primal sense of the word; true love means true fear of hurting the other and a desire to do that which pleases the other. As fr Richard Conrad OP puts it:
"If we love God, if we are His children and friends, then we have a deep concern to do what pleases Him and avoid what would hinder our journey into Him. And that is the Fear which is the Gift of the Holy Spirit, a Fear which goes with love... [With this Gift] we can sense if it's important to God for us to give up some legitimate pleasure or need - and our anxiety is to give it up and please God."
Moreover, Fr Jordan Aumann OP says that Fear of the Lord corresponds to the theological virtue of Hope "which it perfects by motivating the individual to avoid sin out of reverential fear of God... [it is] filial fear born of love and reverence [that] seeks the purity required for union with God."
Why is Fear of the Lord the beginning of wisdom? Its fruition from Love should be indicative, for as we have seen Wisdom and Charity are inseparably linked. Again, Pope Benedict offers some insight into the matter. The Holy Father said:
"The Christian writer Barsanuphius of Gaza (active in the first half of the sixth century) comments on this verse: 'What is the first stage of wisdom if not the avoidance of all that is hateful to God? And how can one avoid it, other than by first asking for advice before acting, or by saying nothing that should not be said, and in addition, by considering oneself foolish, stupid, contemptible and of no worth whatsoever?'Hence, as we journey into love, into the Holy Spirit, we begin with Fear of the Lord, which is that anxiety to do only that which pleases Him and to avoid all that offends Him; it is a journey into greater purity of heart and intention. Let us pray:
However, John Cassian (who lived between the fourth and fifth centuries) preferred to explain that 'there is a great difference between love, which lacks nothing and is the treasure of wisdom and knowledge, and imperfect love, called 'the first stage of wisdom'. The latter, which in itself contains the idea of punishment, is excluded from the hearts of the perfect because they have reached the fullness of love'
Thus, on the journey through life towards Christ, our initial servile fear is replaced by perfect awe which is love, a gift of the Holy Spirit."
Novena Prayer to the Holy Spirit
"By bestowing on us Your Holy Spirit, purify and enlighten our hearts, O Lord. May He come into their depths like the gentle dew and make them fruitful."