I suppose some people emphasize the divine justice and wrath in an attempt to "scare" others into being good and serving God. Yet the Most High does not want us to serve out of fear, but out of love. Whoever knows and lives in God's love will have a holy desire, produced by Grace, to completely dedicate oneself to Our Lord. Our Heavenly Father desires such service from His children. Jesus obeyed the Father's will out of Love for Him (John 14:31), and love is our Maker's attitude towards us. God blesses us so richly out of love and desires a free return of that love from us. This is the meaning of a "love relationship" with the Creator; doing things out of love, not fear of punishment.
GOD IS LOVE
God does not just possess love; He is Divine Love - "Charity" - by very nature (I John 4:8). This, by the way, is why there are Three Persons in the Godhead. Charity is selfless, benevolent, directed toward others; thus it "needs" a beloved, an object of love. Since God is the only Being Who exists eternally, this eternal Beloved would have to be God as well. God could not be Eternal Love unless He was loving someone eternally, thus that someone would be one with Himself.
So for all eternity there is, in the Godhead, a Giver of Love (the Father) and a Receiver of Love (the Son), Whom Scripture calls the Beloved (Ephesians 1:6). That's Two Divine Persons, but what about the Third? The Third Person is the Love Itself, which eternally flows between Giver and Beloved. This Love is essentially Divine, one in nature with the Giver and Beloved, and it is so real and powerful that it is a Third Person: The Holy Spirit. Thus the Triune Godhead is a manifestation of God's living, personal Love.
This infinite Triune Godhead is perfectly self-sufficient. The Eternal Son is equal to the Eternal Father, and so is a most fitting recipient of the Father's Eternal Love. The Spirit of Love is also equal to the Father and Son, and co-eternal with them. Yet God chose to "reach outside" this Eternal Community of Love by creating things other than Himself. He created everything lovingly, fashioning and gently sustaining each creature, enveloping all in His love while remaining essentially distinct from each. The Creator's loving Presence has permeated the cosmos from the very beginning; God is like a living, personal ocean of Love in which all creation is immersed.
The Blessed Trinity reigns over all creatures with great love and tender concern, delighting infinitely in their essential goodness, which is a created reflection of the Divine Goodness. Though essentially distinct from God, creation is a source of His infinite delight and pleasure.
The Inception of Evil
The Church tells us that evil began, not with humanity, but among some of the angels. God, of course, created the angels good, and gave them the ability to freely choose to return His Love and serve Him out of pure love. This also meant they could potentially choose to reject His Love and not serve Him. God did not want them to do that, but He also did not want them to serve them out of compulsion. As He freely chose to create and love them, so He desired them to freely choose to love Him.
Tragically, some of them chose to rebel against the God of perfect Love and Holiness. This act was a "negation" of God; it went contrary to Goodness and so introduced a "not-good" element into the cosmos. This "not-good" is sin, evil, selfishness - the opposite of God's moral nature, which is selfless, humble Love.
The Almighty never stopped being Love, for God cannot change (Malachi 3:10). Yet since evil is contrary to Divine Goodness, God opposed it, knowing it's potential destructiveness to the good creation. Being Sovereign and Love, Our Lord had to take punitive measures against evil. This divine act toward something which threatens creation is called "judgment". It is not a change in God's nature but a "reaction" (so to speak) to something harmful and contrary to the good creation.
The Fall of Humankind
The Creator fashioned the earth, populated it with animal and plant life and then formed human beings - our first parents - according to the divine image and likeness. Like God, they were essentially good, created for fellowship with the Most High. Thus they received the same free will which the angels enjoyed, to that they could choose to return God's love for them.
Yet the Adversary tempted them to disobey God. They listened and so sin entered the human and material creation. This severed their communion with the One Who had blessed them so richly out of an abundance of love. God still loved them after they sinned, but He also foresaw all the pain it would cause them and all their descendents, and hated that sin.
Divine Love and "Hatred"
You see, love and hate are not exactly opposites, they are related. The opposite of both of them is indifference - the lack of emotion or concern. God is Love, so God cannot be indifferent toward anything or anyone. God's concern for us is as infinite as His knowledge of us; even the hairs on our head are numbered (Matthew 10:30). Yet since hatred is not per se opposed to love, divine Love does not exclude all hatred, as we shall see.
One could define hatred as "love's reaction to that which hurts the beloved". Think of someone you love a lot. Now imagine someone else attacking and hurting that loved one (God forbid!). That thought would most likely get you angry. You do not want to see your beloved hurt, so you feel anger - perhaps evenhatred, toward the hypothetical attacker. This is what I mean when I say that hatred is the reaction of love to something (or someone) hurting the beloved.
Since God loves us infinitely, and evil hurts us, God hates evil infinitely. God does not hate us, however; even if we are the ones actually committing the evil. We are essentially God's "very good" creation, yet we bear the wounds of original sin within us. So God loves us as His creatures but hates our sin which He did not create. (That is why Divine Love "separates the deed from the doer", as they say.)
What an awesome truth: God hates our sin because He loves us! And our Maker never stops loving us. Even if we break His Sacred Heart a thousand times, Jesus will still love us the same as He did before we ever sinned - infinitely!
GOD UNDERSTANDS
The God of Scripture is much more loving and understanding toward our weaknesses than we sometimes give Him credit. Psalm 103:13-14 tells us that "As a father pities his children, so the LORD pities those who fear him. For he knows our frame; he remembers that we are dust". God understands our human frailty completely and so pities us like a loving father toward his children.
When a child falls while learning how to walk for the first time, a good parent would not stand over the toddler and scream, "You stupid child! I expected more out of you than that. You should be doing cartwheels by now and you can't even walk!". No, the parent knows the child's weakness, and so has no such delusions about her abilities. So a good parent will simply pick the child up and try again. And so it is with our Heavenly Father, Who perfectly understands our weaknesses and wants to help us overcome them.
How does the Most High understand our feelings and weaknesses? He understands because He created us. An inventor has a pretty good idea of how his or her invention works, having put it together. In a more profound manner, the Creator has total knowledge of all the inner workings of every human being. As King David, wrote, "You have formed my inward parts; you have covered me in my mother's womb...My frame was not hidden from you when I was made in secret, and skillfully wrought in the lowest parts of the earth" (Psalm 139:13-15)
God understands because of the Divine Omniscience. Our Lord simply knows everything about everything. Thus He knows all our feelings, our personal limitations, and every other detail of our lives. This ties in with the first reason - God knows all for He created all.
God is immanent to us all, closer to us than we are to ourselves. "In Him we live and move and have our being" (Acts 17:28). Our Maker is intimately aquainted with everything within us (Psalm 139:1) and lovingly sympathizes with our sufferings and weaknesses.
Finally, God chose to experience our humanity firsthand through the Incarnation. Jesus is 100% human, like us in all things except sin. However, though He never committed a sin, he was not exempt from temptation:
Therefore, He had to be made like His brethern in all things, that He might become a merciful and faithful high priest in things pertaining to God, to make propitiantion for the sins of the people...We do not have a high priest who cannot sympathize with our weakness, but one who had been tempted in all things as we are, yet without sin....For since He Himself was tempted in that which He has suffered, He is able to come to the aid of those who are tempted - Hebrews 2:17; 4:15; 2:18Christ our God has experienced human feelings, limitations, and even temptations firsthand. He knows what it's like to be human, and to be tempted. The Eternal Wisdom has completely identified with us through the Incarnation, and so can sympathize with our weaknesses.
Since the entire Trinity thinks and acts as one, all Three Persons love and understand us.
