I answer with this: If things matter to the Lord Jesus Christ, they should matter to us. All Scripture is given for doctrine, etc. If my main concern with my relationship to my wife is to keep the legal status of married, I would not have to cultivate much in that relationship. If my main desire is to love her, to honor her, to respect her, to please her, to care for her, to grow deeper in love with her- then I have a lot of daily labor as I cultivate that type of relationship.
If I want to maintain my legal status with the Lord Jesus Christ I can do those lowest common denominator things. If I want to fall deeply in love with the Lord Jesus Christ and esteem his smiles higher than the smiles of men and esteem his frowns higher than the frowns of men; than I have some work to do.
Heart-work is hard work indeed. To shuffle over religious duties with a loose and careless spirit, will cost no great difficulties; but to set yourself before the Lord, and to tie up your loose and vain thoughts to a constant and serious attendance upon him: this will cost you something. To attain ease and dexterity of language in prayer and to be able to put your meaning into appropriate and fitting expressions is easy; but to get your heart broken for sin while you are actually confessing it; melted with free grace even while you are blessing God for it; to be really ashamed and humbled through the awareness of God's infinite holiness, and to keep your heart in this state not only in, but after these duties, will surely cost you some groans and travailing pain of soul. -John Flavel