To keep the heart, necessarily supposes a previous work of regeneration, which has set the heart right, by giving it a new spiritual inclination, for as long as the heart it not set right by grace as to in habitual frame, no means can keep it right with God. Self is the poise of the unrenewed heart, which biases and moves it in all its designs and actions; and as long as it is so, it is impossible that any external means should keep it with God.

Man, originally, was of one constant, uniform frame of spirit, held one straight and even course; not one thought or faculty was disordered: his mind had a perfect knowledge of the requirements of God, his will a perfect compliance therewith; all his appetites and powers stood in a most obedient subordination.

Man, by the apostasy, is become a most disordered and rebellious creature, opposing his Maker, as the First Cause, by self-dependence; as the Chief Good, by self-love; as the Highest Lord, by self-will; and as the Last End, by self-seeking. Thus he is quite disordered, and all his actions are irregular. But by regeneration the disordered soul is set right; this great change being, as the Scripture expresses it, the renovation of the soul after the image of God, in which self-dependence is removed by faith; self-love, by the love of God; self-will, by subjection and obedience to the will of God; and self-seeking by self-denial. The darkened understanding is illuminated, the refractory will sweetly subdued, the rebellious appetite gradually conquered. Thus the soul which sin had universally depraved, is by grace restored. This being pre-supposed, it will not be difficult to apprehend what it is to keep the heart, which is nothing but the constant care and diligence of such a renewed man to preserve his soul in that holy frame to which grace has raised it. For though grace has, in a great measure, rectified the soul, and given it an habitual heavenly temper; yet sin often actually discomposes it again; so that even a gracious heart is like a musical instrument, which though it be exactly tuned, a small matter brings it out of tune again; yea, hang it aside but a little, and it will need setting again before another lesson can be played upon it. If gracious hearts are in a desirable frame in one duty, yet how dull, dead, and disordered when they come to another! Therefore every duty needs a particular preparation of the heart. " If thou prepare thine heart and stretch out thine hands toward him," To keep the heart then, is carefully to preserve it from sin, which disorders it; and maintain that spiritual frame which fits it for a life of communion with God.

This includes in it six particulars:

1. Frequent observation of the frame of the heart. Carnal and formal persons take no heed to this; they cannot be brought to confer with their own hearts: there are some people who have lived forty or fifty years in the world, and have had scarcely one hour's discourse with their own hearts. It is a hard thing to bring a man and himself together on such business; but saints know those soliloquies to be very salutary. The heathen could say, "the soul is made wise by sitting still in quietness." Though bankrupts care not to look into their accounts, yet upright hearts will know whether they go backward or forward. "I commune with mine own heart," says David. The heart can never be kept until its case be examined and understood.

2. It includes deep humiliation for heart evils and disorders; thus Hezekiah humbled himself for the pride of his heart. Thus the people were ordered to spread forth their hands to God in prayer, realising the plague of their own hearts. Upon this account many an upright heart has been laid low before God; 'O what a heart have I.' Saints have in their confession pointed at the heart, the pained place: 'Lord, here is the wound'. It is with the heart well kept as it is with the eye; if a small dust get into the eye it will never cease twinkling and watering till it has wept it out: so the upright heart cannot be at rest till it has wept out its troubles and poured out its complaints before the Lord.

3. It includes earnest supplication and instant prayer for purifying and rectifying grace when sin has defiled and disordered the heart. " Cleanse thou me from secret faults" " Unite my heart to fear thy name." Saints have always many such petitions before the throne of God's grace; this is the thing which is most pleaded by them with God. When they are praying for outward mercies, perhaps their spirits may be more remiss; but when it comes to the heart's case, they extend their spirits to the utmost, fill their mouths with arguments weep and make supplication: 'O for a better heart! O for a heart to love God more; to hate sin more; to walk more evenly with God. Lord! deny not to me such a heart; whatever thou deny me: give me a heart to fear thee, to love and delight in thee, if I beg my bread in desolate places.' It is observed of an eminent saint, that when he was confessing sin, he would never give over confessing until he had felt some brokenness of heart for that sin; and when praying for any spiritual mercy, would never give over that suit till he had obtained some relish of that mercy.

4. It includes the imposing of strong engagement upon ourselves to walk more carefully with God, and avoid the occasions whereby the heart may be induced to sin. Well advised and deliberate vows are, in some cases, very useful to guard the heart against some special sin. " I have made a covenant with mine eyes," says Job. By this means holy men have overawed their souls, and preserved themselves from defilement.

5. It includes a constant and holy jealousy over our onto hearts. Quick-sighted self-jealousy is an excellent preservative from sin. He that will keep his heart, must have the eyes of the soul awake and open upon all the disorderly and tumultuous stirrings of his affections; if the affections break loose, and the passions be stirred, the soul must discover it, and suppress them before they get to a height. 'O my soul, dost thou well in this? My tumultuous thoughts and passions, where is your commission?' Happy is the man that thus feareth always. By this fear of the Lord it is that men depart from evil, shake off sloth and preserve themselves from iniquity. He that will keep his heart must eat and drink with fear, rejoice with fear, and pass the whole time of his sojourning here in fear. All this is little enough to keep the heart from sin.

6. It includes the realising of God's presence with us, and setting the Lord always before us. This the people have found a powerful means of keeping their hearts upright, and awing them from sin. When the eye of our faith is fixed upon the eye of God's omniscience, we dare not let out our thoughts and affections to vanity. Holy Job durst not suffer his heart to yield to an impure, vain thought, and what was it that moved him to so great circumspection? He tells us, "Doth not He see my ways, and count all my steps?"

In such particulars as these do gracious souls express the care they have of their hearts. They are careful to prevent the breaking loose of the corruptions in time of temptation; careful to preserve the sweetness and comfort they have got from God in any duty. This is the work, and of all works in religion it is the most difficult, constant, and important work.

1. It is the hardest work. Heart-work is hard work indeed. To shuffle over religious duties with a loose anal heedless spirit, will cost no great pains; but to set thyself before the Lord, and tie up thy loose and vain thoughts to a constant and serious attendance upon him; this will cost thee something. To attain a facility and dexterity of language in prayer, and put thy meaning into apt and decent expressions, is easy; but to get thy heart broken for sin, while thou art confessing it; melted with free grace while thou art blessing God for it; to be really ashamed and humbled though the apprehensions of God's infinite holiness, and to keep thy heart in this frame, not only in, but after duty, will surely cost thee some groans and pains of soul. To repress the outward acts of sin, and compose the external part of thy life in a laudable manner, is no great matter; even carnal persons, by the force of common principles, can do this: but to kill the root of corruption within, to set and keep up an holy government over thy thought, to have all things lie straight and orderly in the heart, this is not easy.

2. It is a constant work. The keeping of the heart is a work that is never done till life is ended. There is no time or condition in the life of a Christian which will suffer an intermission of this work. It is in keeping watch over our hearts, as it was in keeping up Moses' hands while Israel and Amalek were fighting. No sooner do the hands of Moses grow heavy and sink down, than Amalek prevails. Intermitting the watch over their own hearts for but a few minutes, cost David and Peter many a sad day and night.

3. It is the most important business of a Christian's life. Without this we are but formalists in religion: all our professions, gifts and duties signify nothing. " My son, give me thine heart," is God's request. God is pleased to call that a gift which is indeed a debt; he will put this honor upon the creature, to receive it from him in the way of a gift; but if this be not given him, he regards not whatever else you bring to him. There is only so much of worth in what we do, as there is of heart in it. Concerning the hears, God seems to say, as Joseph of Benjamin, "If you bring not Benjamin with you, you shall not see my face." Among the Heathen, when the beast was cut up for sacrifice, the first thing the priest looked upon was the heart; and if that was unsound and worthless the sacrifice was rejected. God rejects all duties (how glorious soever in other respects) which are offered him without the heart. He that performs duty without the heart, that is, heedlessly, is no more accepted with God than he that performs it with a double heart, that is, hypocritically.

Thus I have briefly considered what the keeping of the heart supposes and imports. I proceed,