When you first saw the cross, and understood the meaning of the blood, you got your conscience 'purged from dead works' (Heb 9:14); and it was this cleansing of the conscience that gave you peace. It was not that you ceased to be a sinner, or lost the consciousness of being one, but you had found something which pacified your conscience in a righteous way, and made you feel towards the law and the Lawgiver just as if you had never been guilty.
It is by keeping constantly before your eyes this blood of propitiation that you will keep your conscience clean and your soul at peace. It is this blood alone that can wipe off the continual sins that are coming across your conscience, and which, if not wiped off immediately, will effectually stain it, and cloud your peace. You know how the steel of the finest sword may be rusted by a drop of water. Yet if the water is not allowed to remain, but is wiped away as soon as it falls, it harms not the steel, and no rust ensues. If, however, through neglect or otherwise, the water is allowed to remain, rust will follow, destroying both the edge and brightness of the weapon. So it is with sin. The moment it falls upon the conscience, the blood must be applied; else dimness and doubting will be the consequence. Remember it is the blood, the blood alone; that can remove these.
If, when you sin, you do not go at once to this and be washed and pardoned, but betake yourself to anything else first, you will only make bad worse. If you shrink from going directly to Christ and His blood; if you try to slip gradually near in some roundabout way, as if you hoped, by the time you reach the fountain, to get quit of part of the sin, so as not to be quite so bad as at the moment when you committed it, you will not cleanse the conscience, but leave the burden and the stain just where they were. If you say, 'But I am so ruffled with the sin, so cast down and ashamed at the thought of what I have done, that I dare not go at once to the blood; I must pray or read myself into a better frame, and then I will go and be washed'; you are denying God's method of purging the conscience; you are undervaluing the blood; you are reverting to your old ways of self-righteousness; and you are preventing the restoration of lost peace; for you are putting something between your conscience and the blood.
Keep, then, the conscience clean by continual application to the blood; and you will find that this, instead of encouraging you to sin, will make you more ashamed and afraid of it, than if you had got quit of it in some self-righteous way of your own. What more likely to make you fear and hate it than being compelled to go with it constantly to God, and deal with Him directly about its pardon?
Cultivate a tender conscience; but beware of a diseased and morbid one. The former takes an honest, straightforward view of truth or duty, and acts accordingly. The latter, overlooking what is broad and great, is always on the hunt for trifles, quibbling and questioning about things of no importance. Thus a stiff Christianity is produced, an artificial religion, very unlike the erect but easy walk of one who possesses the liberty of Christ. Be natural, be simple, be easy in word and manner, lest you seem as one acting a part. Cherish a free spirit, a large heart, and a clear conscience, like the apostle, who, though he pitied the 'weaker brethren' (1 Cor 8:9-13), refused to allow his liberty in Christ to be narrowed by another man's morbid conscience. Certainly beware of little sins; but be sure that they are sins. Omit no little duties; but see that they are duties. A tender and tranquil conscience does not make a man crotchety or troublesome, far less morose and supercilious; it makes him frank, cheerful, brotherly, and obliging, in the family, in the shop, in the congregation, in the market-place, whether he be poor or rich; so that others cannot help seeing how pleasantly he goes out and comes in, 'eating his meat with gladness and singleness of heart' (Acts 2:46), and so 'adorning the doctrine of God his Saviour in all things' (Titus 2:10).