Pope Benedict XVI wrote an encyclical called "Deus Caritas est," meaning God is Love. Many people were surprised that this was the topic of his first encyclical, thinking that he would instead choose a topic that addressed some sort of firm affirmation of Church dogma. Yet Benedict was entirely correct to make this his first encyclical, as he is rebuilding understanding of the roots of the Catholic Church from its foundation, which is God's love, to the reality of today when so many are lost. So he was not only correct to make his first encyclical about the foundation of everything in the universe, its structure and its life, existing because God is Love, but he's continued to build through, for example, his books on Jesus of Nazareth and his book on the Apostles. Here is the opening paragraph of "Deus Caritas est:"
1. “God is love, and he who abides in love abides in God, and God abides in him” (1 Jn 4:16). These words from the First Letter of John express with remarkable clarity the heart of the Christian faith: the Christian image of God and the resulting image of mankind and its destiny. In the same verse, Saint John also offers a kind of summary of the Christian life: “We have come to know and to believe in the love God has for us”.
Take a close look at the quote from Jesus cited by St. John, "God is love, and he who abides in love abides in God, and God abides in him." Let that sink in for a minute. Most people assume that because God is love, that everyone is loved by God no matter what they do. But think about what Jesus is saying, "he who ABIDES in love abides in God, and God abides in him." While everyone is God's children, nowhere in the Bible or Qur'an is there a guarantee that God loves anyone who does not "abide in love." And there is no guarantee that "God abides in him [or her]" if the person does not ABIDE IN LOVE.
There is no guarantee that God loves every person, if the person is not abiding in love of God. That does not mean God is abandoning sinners, if they are sinners who acknowledge God exists and they are striving to abide in love. But people need a cold shower to realize that God can stop loving a person, if the person makes no effort to abide in love of God.
This is what is meant by "fear of the Lord." It is not fear of being punished by God, but it is fear of losing the love of God. It is possible to position one's self to totally rebuff God's love so that at some point, one is truly without God and on one's own. God starts by loving every living thing, every little baby, and giving that baby a soul, a guardian angel, and the continual ability to turn to God in love and trust and communicate with him. When a person totally denies the existence of God by not fearing the loss of God's love, then that person probably will lose the love of God. So fear of God is not referring to fear of being "smited" by God, but fear of losing the love and care of God through one's own hardening of heart. The Bible warns against hardening of heart against God, saying that at some point, God will give up on a person and allow hardening of heart to proceed.
God is no longer to be able to care for, as in nurse and tend to, people who have shut down communications and love with God. Those who place themselves above God find themselves getting their implicit wish: they remove themselves from God and from his sheltering love. They are on their own in a world of human created sin.
This is why Jesus warns that sins against the Holy Ghost (the Holy Spirit) will not be forgiven, for the Spirit is the bearer of God's love and wisdom to humankind. For example, the sin of "presumption upon God's mercy" refers not only to cynical manipulation of God's power to forgive many, many times, but also presuming that God will always love a human who never attempts to find, love, and value God.