Those modern non-doctrinal / anti-doctrinal "Christians" who would blather, "man looks on the outward appear appearance but God looks on the heart"—to justify their own immorality / rebellion against God, don't even realize that they condemn themselves in so saying. They don't realize that what they are saying, in essence, is, "yes, although you may notice by my outward actions and attitude that I am not in conformity with the Word of God—you don't know the half of it and God knows the utter naked bankruptcy of my reprobate heart and nature because He sees me how I really am, not how I half-heartedly pretend to be!"
8This people draweth nigh unto me with their mouth, and honoureth me with their lips; but their heart is far from me. 9But in vain they do worship me, teaching for doctrines the commandments of men. (Matthew 15)
Christ was quoting
Wherefore the Lord said, Forasmuch as this people draw near me with their mouth, and with their lips do honour me, but have removed their heart far from me, and their fear toward me is taught by the precept of men.
One cannot keep the "spirit" of the law if he rejects the letter; it is an impossibility. However, one can keep the letter, without the spirit, but that is not righteousness or obedience, but mere compliance. A slave can do what he master orders, but that doesn't mean that he likes it or thinks kind thoughts of the master.
We are called to both. We are called to the letter of what God commanded because God is Holy and He commanded us to be holy as He is Holy. However, it is not within man to do what is right, and God said, on their own, there is none that do good, no not one; all have gone astray, none even seek God. If any do seek God or desire to do what is right, that is only because the Holy Spirit of God has drawn them to seek God and empowers them and gives them the desire to do what is right (if, that is, they do any more than mere lipservice; going through partial appearance of submission and obedience, while in reality, doing what the flesh wants instead. One cannot be in partial submission. One either is or is not. Those who think that they are, because they can point to one or two things, are in delusion.
"19What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own? 20For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God’s." (I Corinthians 6)
God is not fooled by those who pretend. Why then do they pretend? Do they think that God is stupid?
No, the majority reject truth and doctrine and instead entertain their humanist fantasy that God is how they in their minds want Him to be, not the way that He said that He is. They don't think that God will ever judge anyone, because, in their minds, they think that if God ever did judge anyone, then He would not be "good" (based upon their carnal, fallen, perversion of the concept of Good; which is defined by what God is and Decrees, not based upon their sinful notions).
It is a fearful thing to fall into the Hands of the Living God.
If they actually believed the Bible, they would fear God and obey Him; knowing that He is Holy and His Holiness demands Justice.
We are not saved by obedience (since none can perfectly obey and no amount of not sinning can unsin previous sin; and no amount of not sinning can remove the sin nature, which has contaminated us since conception). We are saved UNTO obedience.
Obedience, good works, keeping the Law, bearing fruit are all synonyms. Man does not invent his own "menu" of fruit, good works, obedience... God established it from the beginning and it never changes. We are to conform to what God commanded; God will never compromise and condescend to meeting us halfway concerning what we are and are not willing to obey. The more we grow in conformity with Christ, the more we will grow in obedience to God. It should be a day process of growth and maturation (not merely aging) and each day we should be more like Christ, more Godly, more spiritual, more obedient, than we were the day before. If we are not, then such days of our lives are wasted—squandered, gambled away on the lusts of the flesh and the carnal mind, rather than being in submission to God.
God will not be fooled. He knows what He Himself looks like. He knows what Christ looks like. He knows what His Word looks like. Those who do not bear His Image are bastards, and not sons; and He is not fooled.
As I explain in my booklet, Void of Offense to God and Man, We are His servants, slaves, ambassadors, sons. Our job is to represent Him in all we do, in our thoughts, attitude, words, and deeds. When we do not, we are AWOL. The carnal mind is not in submission to the Word of God, neither can it be. To be a friend of the world (which includes the flesh, the carnal self) is to be the enemy of God. This I say, walk in the Spirit and ye shall not fulfill the lusts of the flesh... One cannot obey God and be ignorant concerning His Word, His Law, His Doctrine. If you never asked your boss what he wanted you to do, and you did not understand the job, and you did not read the company manual, how do you expect to please the boss, keep your job, earn a paycheck? You can't go to work and then do what you want all day long, instead of what the boss requires. Christ says that those who are not with Him doing what He commanded, are against Him doing that which undoes His Work. That type of person is called an enemy—and a good many (if not the majority) who think of themselves as "Christians" fall into that category.
"Examine yourselves, whether ye be in the faith; prove your own selves. Know ye not your own selves, how that Jesus Christ is in you, except ye be reprobates?" (II Corinthians 13:5)
Examine yourselves with what? prove yourselves how? Look at the model of what God's Word declares that we are to be. Then look at yourself in the mirror—with the lights on full; or better yet, take the mirror outside at noon on a cloudless day. Compare the two.
Reality is not how you think yourself to be; but what you really are. I still think of myself as Charles Atlas, 25 years old, and a head of hair. Whenever I walk by a mirror and see what I am now, I stop, bewildered, and say, "Okay, WHO are YOU and what did you do with ME?" Most Christians are the same way concerning spiritual life.
He that hath ears to hear... [and that can only be those whose ears God has opened; deaf man cannot open their own ears; blind men cannot heal their own eyes; dead men cannot bring themselves back to life; "The wind bloweth where it listeth [determines]... so is everyone that is born of the Spirit." (John 3:8) "Whereunto He called you by our Gospel..." (II Thessalonians 2:14) "For we are His workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them." (Ephesians 2:10)]