“Teacher, which is the great commandment in the Law?” And He said to him, “You shall love the Lord your God with all your heart and with all your soul and with all your mind. This is the great and first commandment. And a second is like it: You shall love your neighbor as yourself. On these two commandments depend all the Law and the Prophets” (Matt. 22:36-40).
Jesus chose one law from among 613 when He answered the lawyer. This is the basis on which all obedience to God's laws will be judged.
In the same discussion Jesus rebukes people for diligently observing tithes while neglecting weightier matters (Matt. 23:23). What made such matters "weightier"?
He names mercy, justice, and faithfulness. These are weightier, not because other commands are unimportant, but because obedience to any other command is meaningless unless motivated by love for God, faithfulness to Him, and a true desire for mercy and justice.
Tithing mint, dill, and cumin means nothing if it does not come from a heart which knows justice, mercy, and faithfulness–the fruits of a heart which truly loves God.
Acceptably obeying "ALL the law and prophets" depended on the first and second commands. This is why Jesus says, "You should have practiced the latter, without neglecting the former."
His point is not, "Love God, and the rest is just details." No teaching or commandment of God may safely be ignored. They all come from the same Source–"He who said, 'Do not commit adultery,' also said, 'Do not murder'" (Jas. 2:11).
It is sin to "judge the law" of God (Jas. 2:10-12). We must be determined doers of the Word, not judges of what portion is "important."
A heart that tries to distinguish the "important" from the "trivial" in God's Word can never be acceptable to Him.
Jesus was concerned with all of His Father's will–"so that the world may know that I love the Father, I do exactly as the Father commanded Me" (Jn. 14:31).
His chosen apostles understood the necessity and importance to "teach all He had commanded," and "declaring the whole counsel of God" (Matt. 28:20; Acts 20:27).
Do we share the same conviction?
The man who gives himself wholeheartedly to Christ will be satisfied with nothing less than a lifetime of striving to do all the Lord asks of him (Lk. 17:10).
That kind of servant will not make distinctions in God's laws (accepting some while discounting others) nor salve his conscience by saying, "Well, at least my heart is right."
Quite the opposite in fact. If I understand the first and greatest command, then the "right heart" is not ever satisfied with itself.
The right heart strives to do all God's will while recognizing its own unworthiness, continually praying for forgiveness (1 Jn. 1:8-10; Lk. 18:13).
We strive or press toward perfection, and die without ever having reached our ideal (Phil. 3:12-16).
Sinlessness is so far above man that John says, "If we say that we have no sin, we deceive ourselves, and the truth is not in us" (1 Jn. 1:8). Reaching the ideal is beyond this life, but striving for it is to be done here and now. So, are we striving? We have fellowship with God through forgiveness in Christ (1 Jn. 2:1). Such love and grace from God should move us to have and practice the same, to see all of His will as essential, and submit to all. One who fulfills the first and greatest command will consider ALL of God's requirements equally important, learning to "walk in a manner worthy of the Lord, to please Him in ALL respects" (Col. 1:10).