- God's law for Adam and Eve was fairly simple: Take dominion, multiply, eat fruit and herbs (Gen 1:28-29), tend the garden but don't eat of the wrong tree (Gen 2:15-17). And after the fall: "now you have to grow your own food" (Gen 3:17-19)
- God's instruction to Cain (Gen 4:7) was fairly simple: Do well and rule over sin (implicit in this is a necessary recognition of what sin is).
- God's law for Noah (Gen 9:3-7) was a little less simple: Multiply, add meat to your diet but not the blood, and avenge murder.
- God's law for Abraham (Gen 18:19) wasn't really specified, but God apparently chose him because he would teach his children to obey God's commands, and to act justly and judge rightly, which contains an implicit recognition of what is just and right.
- God's law for Israel (Ex-Deut) was much more complicated. Someone else already commented that it was to keep the Jews healthy, no doubt to get them to last long enough for the savior to be born, but also to point toward Christ's sacrifice.
- God's law for the gentile church (Acts 15:28-29) seemed to reiterate the simplicity of Noah's: Don't eat meat sacrificed to idols, or bloody or strangled meat, and don't fornicate. Plus, "do well" again (again with an implicit acknowledgement that they will know what it means to "do well").
- Jesus said his yoke is easy and his burden is light (Matt 11:28-30), but doesn't suggest there is no yoke or burden. And He condenses the whole of the law into 2 commands: Love God and love your neighbor.(Matt 22:37-40) Then He said that to love Him means to keep His commandments (John 14:15,21)
- Paul said to imitate him like he imitated Christ (who did everything the Father told him to do), but he listed things that describe people that won't be in the kingdom of God, including both the general term "wicked" along with what "wicked" people do. (1 Cor 6:9-11).
- David loved God's law. Ps 119 is a love song to the law of God! And David was a man after God's own heart.
So my conclusion is that God wants people in His kingdom who want to do His law--whatever that happens to be. And if you don't want to do what He commands, He doesn't want you there. Logically, that makes sense: If you don't want to do what the king says, why would you ever want to be in that king's kingdom? A kingdom is a place ruled by a king, meaning the king gets to tell people what to do. Why go to a kingdom where you don't like what the ruler says to do?
And if God truly is all wise and loves the creatures He made in His image, then the things He tells them to do are not capricious, but are for their good. When we believe in Him, then we should believe this about Him.
In addition, there are a few things kings do when they find that someone is not obeying them in their kingdom: they either banish them (refuse to let them be in that kingdom) or restrain them (put them in a prison, away from the nice places) or kill them. All of these ideas are used to describe both the state of man after the fall and the kingdom of God:
Gen 2:17 (threat of death)
Gen 3:23 (banishment)
Gen 3:24 (restraining)
Luke 13:27-28 (banishment)
Rev 20:1-3 (restraining)
Rev 20:14-15 ("2nd death" and banishing from kingdom and restraining--they can't leave the lake of fire)