If all that has been said by way of inducement be not enough, I have yet some motives to offer you:
1 The studying, observing, and diligently keeping your own heart, will surprisingly help you to understand the deep mysteries of religion. An honest, well-experienced heart is an excellent help to the head. Such a heart will serve for a commentary on a great part of the Scriptures. By means of such a heart you will have a better understanding of divine things than the most learned (graceless) man ever had, or call have; you will not only have a clearer, but a more interesting and profitable apprehension of them. A man may discourse orthodoxy and profoundly of the nature and effects of faith, the troubles and comforts of conscience, and the sweetness of communion with God, who never felt the efficacy and sweet impression of these things upon his own soul. But how dark and dry are his notions compared with those of an experienced Christian!
2 The study and observation of your own heart will powerfully secure you against the dangerous and infecting errors of the times in which you live. For what think you is the reason why so many professors have departed from the faith, giving heed to fables? why have so many been led away by the error of the wicked? why have those who have sown corrupt doctrines had such plentiful harvests among us, but because they have met with a race of professors who never knew what belongs to practical godliness and the study and keeping of their hearts?
3 Your care and diligence in keeping your heart will prove one of the best evidences of your sincerity. I know no external act of religion which truly distinguishes the sound from the unsound professor. It is marvellous how far hypocrites go in all external duties; how plausibly they can order the outward man, hiding all their indecencies from the observation of the world. But they take no heed to their hearts; they are not in secret what they appear to be in public; and before this test no hypocrite can stand. They may, indeed, in a fit of terror, or on a death-bed, cry out of the wickedness of their hearts; but such extort ed complaints are worthy of no regard. No credit, in law, is to be given to the testimony of one upon the rack, because it may be supposed that the extremity of his torture will make him say any thing to get relief. But if self-jealousy, care and watchfulness be the daily workings and frames of your heart, you have some evidence of your sincerity.
4 How comfortable and how profitable would all ordinances and duties be to you, if your heart was faithfully kept. What lively communion might you have with God every time you approach him, if your heart was in a right frame! You might then say with David, “My meditation of Him shall be sweet.” It is the indisposition of the heart which renders ordinances, and secret duties so comfortless to some. They strive to raise their hearts to God, now pressing this argument upon them, then that, to quicken and affect them; yet they often get nearly through the exercise before their hearts begin to be interested in it; and some times they go away no better than they came. But the Christian whose heart is prepared by being constantly kept, enters immediately and heartily into his duties; he outstrips his sluggish neighbor, gets the first sight of Christ in a sermon, the first seal from Christ in a sacrament, the first communication of grace and love in secret prayer. Now if there be any thing valuable and comfortable in ordinances and private duties, look to your heart and keep it, I beseech you.
5 An acquaintance with your own heart will furnish you a fountain of matter in prayer. The man who is diligent in heart-work, will be richly supplied with matter in his addresses to God. He will not be confused for want of thoughts; his tongue will not falter for want of expressions.
6 The most desirable thing in the world, viz, the revival of religion among a people, may be effected by means of what I am urging upon you.
O that I might see the time when professors shall not walk in a vain show; when they shall please themselves no more with a name to live, while they are spiritually dead; when they shall be no more a company of frothy, vain persons; but when holiness shall shine in their conversation, and awe the world, and command reverence from all that are around them; when they shall warm the heart of those who come near them, and cause it to be said, God is in these men of a truth. And may such a time be expected? Until heart-work becomes the business of professors, I have no hope of seeing a time so blessed! Does it not grieve you to see how religion is contemned and trampled under foot, and the professors of it ridiculed and scorned in the world? Professors, would you recover your credit? would you obtain an honorable testimony in the consciences of your very enemies? Then keep your hearts.
7 By diligence in keeping our hearts we should prevent the occasions of fatal scandals and stumbling-blocks to the world. Wo to the world because of offences!
8 Keep your heart faithfully, and you will be prepared for any situation or service to which you may be called. This, and this only can properly fit you for usefulness in any station; but with this you can endure prosperity or adversity; you can deny yourself, and turn your hand to any work. Thus Paul turned every circumstance to good account, and made himself so eminently useful. When he preached to others, he provided against being cast away himself: he kept his heart; and every thing in which lie excelled seems to have had a close connection with his diligence in keeping his heart.
9 If the people of God would diligently keep their hearts, their communion with each other would be unspeakably more inviting and profitable. Then “how goodly would be thy tents, O Jacob, and thy tabernacles, O Israel!” It is the fellowship which the people of God have with the Father and with the Son that kindles the desires of others to have communion with them. I tell you, that if saints would be persuaded to spend more time and take more pains about their hearts, there would soon be such a divine excellence in their conversation that others would account it no small privilege to be with or near them. It is the pride, passion and earthliness of our hearts, that has spoiled Christian fellowship. Why is it that when Christians meet they are often jarring and contending, but because their passions arc unmortified? Whence come their uncharitable censures of their brethren, but from their ignorance of themselves? Why are they so rigid and unfeeling toward those who have fallen, but because they do not feel their own weakness and liability to temptation? Why is their discourse so light and unprofitable when they meet, but because their hearts are earthly and vain? But now, if Christians would study their hearts more and keep them better, the beauty and glory of communion would be restored. They would divide no more, contend no more, censure rashly no more. They will feel right one toward another, when each is daily humbled under a sense of the evil of his own heart.
10 Lastly: — Keep your heart, and then the comforts of the Spirit and the influence of all ordinances will be more fixed and lasting than they now are.
And do the consolations of God seem small to you? Ah, you have reason to be ashamed that the ordinances of God, as to their quickening and comforting effects, should make so light and transient an impression on your heart.
Now, reader, consider well these special benefits of keeping the heart which I have mentioned. Examine their importance. Are they small matters? Is it a small matter to have your understanding assisted? your endangered soul rendered safe? your sincerity proved? your communion with God sweetened? your heart filled with matter for prayer? Is it a small thing to have the power of godliness? all fatal scandals removed? an instrumental fitness to serve Christ obtained? the communion of saints restored to its primitive glory? and the influence of ordinances abiding in the souls of saints? If these are no common blessings, no ordinary benefits, then surely it is a great and in dispensable duty to keep the heart with all diligence.
And now are you inclined to undertake the business of keeping your heart? are you resolved upon it? I charge you, then, to engage in it earnestly. Away with every cowardly feeling, and make up your mind to encounter difficulties. Draw your armor from the word of God. Let the word of Christ dwell in you richly, in its commands, its promises, its threatenings; let it be fixed in your understanding, your memory, your conscience, your affections. You must learn to wield the sword of the Spirit (which is the word of God) familiarly, if you would defend your heart and conquer your enemies. You must call yourself frequently to an account; examine yourself as in the presence of the all seeing God; bring your conscience, as it were, to the bar of judgment. Beware how you plunge yourself into a multiplicity of worldly business; how you practise upon the maxims of the world; and how you venture at all to indulge your depraved propensities. You must exercise the utmost vigilance to discover and check the first symptoms of departure from God, the least decline of spirituality, or the least indisposition to meditation by yourself and holy conversation and fellowship with others. These things you must undertake, in the strength of Christ, with invincible resolution in the outset. And if you thus engage in this great work, he assured you shall not spend your strength for naught; comforts which you never felt or thought of will flow in upon you from every side. The diligent prosecution of this work will constantly afford you the most powerful excitements to vigilance and ardor in the life of faith, while it increases your strength and wears out your enemies. And when you have kept your heart with all diligence a little while; when you have fought the battles of this spiritual warfare, gained the ascendancy over the corruptions within, and vanquished the enemies without, then God will open the gate of heaven to you, and give you the portion which is promised to them that overcome. Awake then, this moment; get the world under your feet pant not for the things which a man may have, and eternally lose his soul; but bless God that you may have his service here, and the glory hereafter which he appoints to his chosen.
“Now the God of peace, that brought again from the dead our Lord Jesus, that great Shepherd of the sheep, through the blood of the everlasting covenant, make you perfect in every good work to do his will, working in you that which is well pleasing in his sight, through Jesus Christ; to whom be glory for ever and ever. Amen.”