Thomas Brooks in his The Golden Key to Open Hidden Treasures gives an extended discourse on the necessity of universal obedience:
First, It is to no purpose for a man to turn from, some sins, if he does not turn from all his sins….
Secondly, Partial obedience is indeed no obedience; it is only universal obedience that is true obedience…
Thirdly, Partial obedience tends to plain atheism; for by the same reason that you slight the will of God in any commandment, by the same reason you may despise his will in every commandment; for every commandment of God is his will, and it is ‘holy, spiritual, just, and good.’
Fourthly, God requires universal obedience….
Fifthly, Partial obedience is an audacious charge against God himself, as to his wisdom, or power, or goodness; for those statutes of God which you will not come up unto, either they are as righteous as the rest, and as holy as the rest, and as spiritual as the rest, and as good as the rest, or they are not. If they be as holy, spiritual, just, righteous, and good as the rest, why should you not walk in them as well as in the rest?
Sixthly, God delights in universal obedience, and in those that perform it….
Seventhly, There is not any one statute of God but it is good and for our good; ergo, we should walk in all his statutes….
Eighthly, Universal obedience is the condition upon which the promise of mercy and salvation runs…
Ninthly, Our hearts must be perfect with the Lord our God….
Tenthly, If the heart be sound and upright, it will yield entire and universal obedience: Ps. 119:80, ‘Let my heart be sound in thy statutes, that I may not be ashamed;’ and verse 6, ‘Then shall I not be ashamed when I have respect to all thy commandments.’ By these verses, compared together, it appears that then the heart is sound and sincere, when a man has respect unto all God’s commandments. Without a universal obedience, a man can never have that ‘hope which maketh not ashamed.’
Eleventhly, Either we must endeavour to walk in all the statutes of God, or else we must find some dispensation or toleration from God to free us, and excuse us and hold us indemnified, though we do not walk in all of them.
Twelfthly, The precious saints and servants of God, whose examples are recorded, and set forth for our imitation, they have been very careful to perform universal obedience.
Thirteenthly, Universal obedience speaks out the strength of our love to Christ, and the reality of our friendship with Christ,
Fourteenthly, Universal obedience will give most peace, rest, quiet, and comfort to the conscience. Such a Christian will be as an eye that hath no mote to trouble it; as a kingdom that hath no rebel to annoy it; as a ship that hath no leak to disturb it: Ps. 119:165, ‘Great peace have they which love thy law, and nothing shall offend them.’
Fifteenthly Man’s holiness must be conformable to God’s holiness:
Sixteenthly, The holiness of a Christian must be conformable to the holiness of Christ, ‘
Seventeenthly, Servants must obey their earthly masters, not in some things only, but in all things, to wit, that are just and lawful: Titus 2:9, ‘Exhort servants to be obedient to their own masters, and to please them well in all things.’ What master will be content that his servant should choose how far forth he will observe and do those things which he doth require of him? much less may we think that such arbitrary and partial performances will please that God who is our heavenly Master.
Eighteenthly, The promises of mercy, both spiritual and temporal, are made over to universal obedience, 1 Kings 6:12, 13; Deut. 28:1–3; Ezek. 18:21, 22, 27, 28. Turn to all these promises and dilate on them, &c.
Nineteenthly, One sin never goes alone, as you may see in the falls of Adam and Eve, Lot, Abraham, Noah, Jacob, Joseph, Job, David, Solomon, Peter, Ahab, Judas, Jeroboam. One sin will make way for more; as one little thief can open the door to let in many great ones. Satan will be sure to nest himself, to lodge himself in the least sins, as birds nest and lodge themselves in the smallest branches of the tree, and there he will do all he can to hatch all manner of wickedness. A little wedge makes way for a greater; and so do little sins make way for greater.
Twentiethly, The reasons of turning from sin are universally binding to a gracious soul. There are the same reasons and grounds for a penitent man’s turning from every sin as there is for his turning from any one sin.
Twenty-firstly, One sin allowed and lived in will keep Christ and the soul asunder. As one rebel, one traitor, hid and kept in the house, will keep a prince and his subjects asunder; or as one stone in the pipe will keep the water and the cistern asunder; so here. But,
Twenty-secondly, One sin allowed and lived in will unfit a person for suffering; as one cut or shot in the shoulder may hinder a man from bearing a burden. Will he ever lay down his life for Christ, that can’t, that won’t lay down a lust for Christ? But,
Twenty-thirdly, One sin allowed and lived in is sufficient to deprive a man for ever of the greatest good. One sin allowed and wallowed in will as certainly deprive a man of the blessed vision of God, and of all the treasures, pleasures, and delights that be at God’s right hand, as a thousand. One sin stripped the fallen angels of all their glory; and one sin stripped our first parents of all their dignity and excellency, Gen. 3:4, 5. One fly in the box of precious ointment spoils the whole box; one thief may rob a man of all his treasure; one disease may deprive a man of all his health; and one drop of poison will spoil the whole glass of wine: and so one sin allowed and lived in will make a man miserable for ever. One millstone will sink a man to the bottom of the sea, as well as a hundred. It is so here. But,
Twenty-fourthly, One sin allowed and lived in will eat out all peace of conscience. As one string that jars will spoil the sweetest music; so one sin countenanced and lived in will spoil the music of conscience. One pirate may rob a man of all he has in this world. But,
Twenty-fifthly and lastly, The sinner would have God to forgive him, not only some of his sins, but all his sins; and therefore it is but just and equal that he should turn from all his sins. If God be so faithful and just to forgive us all our sins, we must be so faithful and just as to turn from all our sins. The plaster must be as broad-as the sore, and the tent1 as long and as deep as the wound. It argues horrid hypocrisy, damnable folly, and wonderful impudency for a man to beg the pardon of those very sins that he is resolved never to forsake, &c.