The care that a parent has is compared to God's love because a parent would care about a son regardless of whether the son is rejecting the parent or has rejected the parent in the past.
This is the reality of the situation between Supreme Being and ourselves at this point. He unconditionally loves us and therefore He is always ready and willing to forgive us, and take care of us. This also illustrates His impartiality. He is attentive to all His children, not necessarily just the better ones.
Jesus also makes an important and revealing statement here regarding "evil." He says:
“If you, then, though you are evil, know how to give…”
The assumption of Jesus within this text is that the people he is speaking to - the crowd, his students and disciples - are all "evil." Notice that "evil" is not being described as some alien-looking guy with big horns.
Rather, Jesus clearly indicates the people around him -- those he was speaking to -- are "evil." Why?
And if Jesus' disciples and students were "evil" what to speak of us?
We must also realize that each of us living self-centered lives in physical bodies, ignoring the Supreme Being in all or some aspect of our lives, is "evil." This is because evil is the condition of being self-centered.
Those of us who reside here in the physical world reside here specifically because of our self-centeredness - which gives birth to envy and greed. The spiritual world is that place of selfless love and compassion - and that place where the Supreme Being is the center of everyone's lives.
For those of us who rejected this consciousness, we were given temporary physical bodies to gain the freedom from God we were seeking.
And because God loves us and wants us back, this physical environment is set up re-educate us to the fact that we will only be happy and fulfilled if we resume our innate spiritual consciousness - where the Supreme Being is the center of our lives.
Naturally, we all prefer to be treated fairly and cared for. This is because the Supreme Being cares for us and He treats us all impartially and fairly.
He give us what we need, teaches us with love, and wants us to be spiritually happy.
This doesn’t mean that we always get what we want. Just because we think we are going to be happy if we get a red sports car doesn’t mean that we will be happy if we get the car.
In the same way, a child might think he or she will be happy if he or she has candy for dinner. The child’s parents know better. They know that eating candy for dinner will only lead to blood sugar problems, mood issues and the like. Therefore, because the parents love the child, they will give the child healthy food.
In the same way, God teaches through the events of the physical world that material things will not make us happy. For this reason, we usually have to work hard for those things, and then when we get them, we are let down.
This is because the Supreme Being loves us and is trying to teach us what will actually make us happy: to love and serve Him in our natural position within the spiritual realm.
It is for this reason that Jesus says:
"...do to others what you would have them do to you, for this sums up the Law and the Prophets."
In other words, all of the Ten Commandments can be followed if we are truly caring, loving and serving God and His children.
None of the other commandments would be necessary if we were following these.