One of the least appreciated principles in the Bible is the real meaning of "great faith," but it is illustrated by Jesus' praise of the centurion with the sick servant. All that the centurion did was to take an idea—namely, that Jesus was God—and draw from that idea the conclusion that Jesus could heal anyone, wherever situate, and had no need to bring His physical person to the location of the patient. Jesus stated that He had not seen such great faith in Israel (Matthew 8:10).
The opposite state is rendered in the King James version as "ye of little faith." The original term, oligopistoV, could be as well rendered "ye of few faith." The idea is that the faith of the person thus addressed is like a prarie dog; it pops up here, it pops up there, but it isn't everywhere. The divine standard is not that we treat ideas like tools—to be be used for a moment and then set aside—but rather that if an idea is true, that idea should be brought to bear on every other idea in our heads.
Jesus emphasized this point more than once. In a discussion with the Sadducees, Jesus brought to their remembrance the episode when Moses approached the burning bush, and explained to them how this apparently unrelated passage taught that a resurrection—which they did not accept—was indeed coming (Mark 12:18-27).
This is not an isolated instance; there are many doctrines which are demolished by passages that appear on the first glance to be completely unrelated. The doctrine of premillenialism, for instance, is utterly refuted when one properly understands Ephesians 5:25-33. The idea that the "sons of God" in Genesis 6:2 were angels is refuted by Mark 12:25. The fact of the Crucifixion disproves the doctrine of salvation by faith only. The mere fact that the Bible exists disproves predestination. The list goes on, but for this short piece I am going to concern myself with the story of Cain.
As anyone who has ever heard of him knows, Cain, from envy, slew his brother Abel. For this, God punished him. There is a detail in the story that I haven't mentioned yet, but I'll get to it.
Now most of us like to think that we're better than Cain, and I certainly hope that this is true. We haven't killed anybody (which Cain did) and we haven't lied to anybody (which Cain did). Nor have we had other gods before the Lord, made any graven images, taken the Lord our God's name in vain, coveted anything that our neighbor's, stolen, committed adultery, dishnored our father or mother, or borne false witness against our neighbor. In short, we've done none of the Thou Shalt Nots.
If only that were good enough.
Some people think that this is, indeed, good enough to please God. They profess that to get into heaven need only Obey the Commandments, and where they find no overt commandment, they find no cause for condemnation.
I bet Cain wishes he could say that.
That's the detail I mentioned earlier. At no point does God tell Cain not to kill his brother. "Cain?" "Here I am." "Whatever you do, don't kill your brother!" We don't see that. Instead, God gives Cain some pointers on anger management.
We've got some serious thinking to do here. Was it wrong for Cain to kill Abel? Well, God punished him for it, so we'll say "yeah" to that. Did Cain know it was wrong? He tried to cover his tracks, so I'd have to say he did. Was he supposed to know it was wrong, before the fact? Well, God didn't tell him before hand, when He knew Cain was thinking about it, so we have to say that if Cain did not know, his ignorance was an offence for which God was not in a pardoning mood.
In short, there are prohibitions for which God has not issued a direct "Thou Shalt Not," and He does expect us to figure out what they are.
Either that, or God owes Cain an apology.