Imagine a married couple. The spouses are the complete opposites of each other. The husband is highly conscientious. He has full respect for both the law of the land, and moral ethics. He seeks to do the right thing in all cases. The wife, by contrast, is sloppy and reckless. She seeks only her own pleasure.
This couple has a kid, and a dog. Every day, the dog gets a walk, but the couple alternate who takes it. The kid goes with them. On the first day, the father takes the dog out, and it does its business. The father, naturally, takes out a poo bag, scoops it up, and carries it to the bin. The next day, the mother takes the dog, the dog does its business, but the mother just keeps walking. This continues for a few years, and one day, the parents decide the child is now strong and responsible enough to be given full control of the dog.
So, the father hands the kid the lead, and as normally happens, the dog does its business. Just as he has seen his father do, the son pulls out a poo bag, picks up the poo, and takes it to the bin. Of course, this is not a job anyone likes to do, but he does it anyway, because his father does it. The next day, he is once again given control of the lead, this time by his mother. The dog does its business, and the son pulls out a poo bag. "Why are you doing that?" his mother asks in disgust. And so the child decides not to pick up the poo. On the third day, the father hands control of the dog to the son, and once again, the dog does its business. But the son does not pick up the poo. "What are you doing?" the father asks. "Why aren't you picking up the poo?" "Mom says I don't have to", replies the child.
What's the lesson in my analogy? Simply this: Sometimes, doing the right thing is so against our desires that it doesn't take much to convince us not to. The conscientious father represents our Heavenly Father. He always does what is right, and seeks to teach us to do the same. The reckless mother is more open to interpretation. We can compare her to Satan, with his oh so famous line "did God really say...". Or we can compare her to our earthly father, Adam, through whom original sin came. We can compare her to our own flesh, which seeks only its own pleasure.
Regardless of who we compare our reckless mother to, the fact is we are sinners, even sinners under grace. As a result, the right thing is not always easy to do, and so we may ourselves become our reckless mother, failing to heed our conscientious father's voice. God says "you shall", and our flesh says "but shall I?" God says "you shall not", but our flesh says "maybe I shall". Who do we please? Our conscience, or our desires? The answer in the Bible is clear: deny yourself, take up your cross, and follow Christ. If you will not do this, what kind of child of God are you?