When God says, "My way or the highway, He's dead serious!"
God is really big on instructions, so it follows that He likes it when we follow them. The book of Leviticus is a "how-to" book, you could say, (or God's instruction manual--Torah, for instance, means revealed instruction) just filled with them. It is reasonable to assume that a godly person follows instructions and doesn't try to do things his way. Like some are wont to say: If all else fails read the instructions! This is a bad mentality and disastrous spiritually as Nadab and Abihu found out when God consumed them with fire for offering a sacrifice their own way and making a fire their way which God called "strange fire" and God judged immediately because He was so angry. They became examples of those who "do it their way." Frank Sinatra became famous for singing "I Did It My Way" and I'm sure that now after he has died his song led many astray and that he was dead wrong! It is a serious thing to disobey God's instructions and we are responsible for what we have the opportunity to know as David found out when he transported the Ark of the Covenant and when it tipped the person bearing was struck dead because He didn't follow protocol. What do you think the Bible stands for? "Basic Instructions Before Leaving Earth." Disclaimer: The Bible is more than an instruction manual, praise the Lord!
God is a God of order, design, precision, and instruction, not chaos or confusion. We become more godly (God wants you to get organized and be orderly!) by following this pattern and God making us in this image of Christlikeness. We cannot have everybody doing their own thing as it says in the last verse of Judges: "In those days there was no king, everyone did as he saw fit [what was right in his own eyes]" (Judges 21:25). Jesus said there was a "way" and He was it. Knowing Jesus is knowing the way and the first believers were called followers of the Way. In the Army you learn that there is your way and the "Army way" and you learn this lesson pretty fast--you become a quick study! "There is a way which seems right to a man, but the ends thereof are the way of death" (Prov. 16:25). "For forty years I was angry with that generation; I said, "They are a people whose hearts go astray and have not known my ways." Do you know the Way? In another passage, it says: "But my people do not know the rules of the LORD" (Jer. 8:7). Jesus is the logos or logic behind the cosmos and God has a plan for everything under heaven according to Proverbs 16:4: "The LORD works out everything for his own ends--even the wicked for a day of disaster."
People who don't know God are always offering "strange fire" before the Lord and trying to please Him their own way by good works, ritual or religion, morality, philosophy, ethics, etc., and not by faith alone. Nothing that the unbeliever does can please God, for it is all dirty and filthy rags in His sight according to Isaiah 64:6. Do it God's way or don't do it at all because there is no reward for man's way or works. God only rewards what He does through us as His vessels of honor. Finally, the reason God gives instructions is to test our obedience and see if we are serious about being His followers: Israel repeatedly refused and failed to follow instructions--isn't this something we learn in kindergarten?
Jesus condemned the Pharisees, though they followed the instructions, for the same reason God judged Amaziah, (he followed the law, but not with his whole heart). The Pharisees were culpable for externalizing the law and going the motions, as it were, and not doing it from their heart. Today, in our churches we see many who have "memorized the Dance of the Pious" also and have no inward reality--this is exactly what Malachi rebuked Israel for in being frauds at worship. We are to love God with our whole heart, mind, soul, and strength. No one achieves this perfectly in time but in eternity we will be glorified to have the capacity.
What is sin, but doing something our way instead of God's way ("We all, like sheep, have gone astray, each of us has turned to his own way..." (Isaiah 53:6; cf. Judges 17:6; 21:25). It is vain and useless to fight God and do it your own way because God is never frustrated and knows what He is doing and can turn curses into blessings and make everything turn out for the good (cf. Rom. 8:28). Job 42:2 says: "I know that you can do all things, and no plan of yours can be thwarted." As William Cowper said, "God works in mysterious ways, His wonders to perform." ("Cf. Isaiah 45:25, NLT). Soli Deo Gloria!