I saw that some of our ministers do not understand how to preserve their strength so as to be able to perform the greatest amount of labor without exhaustion. Ministers should not pray so loud and long as to exhaust their strength. It is not necessary to weary the throat and lungs in prayer. God's ear is ever open to hear the heart-felt petitions of his humble servants, and he does not require them to wear out the organs of speech in addressing him. It is the perfect trust, the firm reliance, the steady claiming of the promises of God, the simple faith that he is, and that he is a rewarder of all those who diligently seek him, that prevails with God. GW92 152.2
Ministers should discipline themselves, and learn how to perform the greatest amount of labor in the brief period allotted them, and yet preserve a good degree of strength, so that if an extra effort should be required, they may have a reserve of vital force sufficient for the occasion, which they can employ without injuring themselves. Sometimes all the strength they have is needed in order to put forth effort at a given point; and if they have previously exhausted their fund of strength, and cannot command the power to make this effort, all they have done is lost. At times all the mental and physical energies may be drawn upon to make the very strongest stand, to array evidences in the clearest light, and set them before the people in the most pointed manner, and urge them home by the strongest appeals. As souls are on the point of leaving the enemy's ranks and coming upon the Lord's side, the contest is most severe and close. Satan and his angels are unwilling that any who have served under the banner of darkness should take their position under the blood-stained banner of Prince Immanuel. GW92 152.3
I was shown opposing armies who had endured a painful struggle in battle. The victory was gained by neither, and at length the loyal realize that their strength and force are wearing away, and that they will be unable to silence their enemies unless they make a charge upon them, and obtain their instruments of warfare. It is then, at the risk of their lives, that they summon all their powers, and rush upon the foe. It is a fearful struggle; but victory is gained, the strongholds are taken. If at the critical period the army is so weak through exhaustion that it is impossible to make the last charge, and batter down the enemy's fortifications, the whole struggle of days, weeks, and even months, is lost; many lives are sacrificed, and nothing gained. GW92 153.1
A similar work is before us. Many are convinced that we have the truth, and yet they are held as with iron bands; they dare not risk the consequences of taking their position on the side of truth. Many are in the valley of decision, where special, close, and pointed appeals are necessary to move them to lay down their weapons of warfare, and take their position on the Lord's side. Just at this critical period, Satan throws the strongest bands around these souls. If the servants of God are all exhausted, having expended their fund of physical and mental strength, they think they can do no more, and frequently leave the field entirely, to begin operations elsewhere. And all, or nearly all, the time, means, and labor have been spent for naught. Yes, it is worse than if they had never begun the work in that place; for after the people have been deeply convicted by the Spirit of God, and brought to the point of decision, and are left to lose their interest, and decide against these evidences, they cannot as easily be brought where their minds will again be agitated upon the subject. They have in many cases made their final decision. GW92 153.2
If ministers would preserve a reserve force, and at the very point where everything seems to move the hardest, then make the most earnest efforts, the strongest appeals, the closest applications, and, like valiant soldiers, at the critical moment make the charge upon the enemy, they would gain the victory. Souls would have strength to break the bands of Satan, and make their decisions for everlasting life. Well-directed labor at the right time will make a long-tried effort successful, when to leave the labor, even for a few days, will in many cases cause an entire failure. Ministers must give themselves as missionaries to the work, and learn how to make their efforts count to the very best advantage.—Testimonies for the Church 1:645. GW92 154.1