Purge me with hyssop, and I shall be clean

Numbers 31:24 (KJV)
And ye shall wash your clothes on the seventh day, and ye shall be clean, and afterward ye shall come into the camp.

Spiritual warfare with the darkness of this world can leave us with the remains of filthiness which can also tempt us. We are all not perfect, and while attempting to restore another, we may also be tempted with the same sin that we are rebuking. Such is our weakness:
Galatians 6:1 (KJV)
Brethren, if a man be overtaken in a fault, ye which are spiritual, restore such an one in the spirit of meekness; considering thyself, lest thou also be tempted.
Jude 1:23 (KJV)
And others save with fear, pulling them out of the fire; hating even the garment spotted by the flesh.

We ought not to always fight, but take some time to restore ourselves after our battles. Just as the warriors of Israel returned not to the camp immediately after battles but rested and cleansed themselves with hyssop, this is what we are also to do. This is what the apostles did after going out by Christ's commission to battle the kingdom of darkness:
Mark 6:12-13,30-31 (KJV)
And they went out, and preached that men should repent. [13] And they cast out many devils, and anointed with oil many that were sick, and healed them . [30] And the apostles gathered themselves together unto Jesus, and told him all things, both what they had done, and what they had taught. [31] And he said unto them, Come ye yourselves apart into a desert place, and rest a while: for there were many coming and going, and they had no leisure so much as to eat.
Yes, we ought to work, for the harvest is plenty and the many are imprisoned and deceived by Satan. Yes, time is running out and judgment day draws nigh. But we must not continuously work without resting. Why? For we also may fall into temptation. We are still sinners as much as the one who is at fault. We only happen to have the grace from God to be spiritual. We ought to remember that sin is like a fire that can spread unto us. Fire can't be tamed, but it must be extinguished:
Isaiah 9:18 (KJV)
For wickedness burneth as the fire: it shall devour the briers and thorns, and shall kindle in the thickets of the forest, and they shall mount up like the lifting up of smoke.

Spiritual warfare is like fighting fire. We ought to always watch for ourselves that we do not also get burnt. That is why we fight with a spirit of meekness, in a gentle, Christ-like spirit. For Christ's meekness covered the fire of God's wrath against us. He showered us with His grace and mercy, and the fire of wickedness that burnt us up was extinguished. By His love He covered the multitude of our sins. We must also be passionate to not only expose another's sins, but also to cover them as well. We ought to make it our mission to extinguish God's wrath by preaching of the Gospel. The Gospel of Christ's love is what will cease the fire of wickedness that is consuming people. We must preach God's everlasting love that can cover their sins.

It is interesting to note here that the water of purification, by which the soldiers purified themselves outside the camp, consisted of the burnt ashes of a heifer and running water. The burnt ashes signify the suffering of Christ. Our sins burnt up Christ by the wrath of God and His soul became like nothing but ashes. But by this ashes of Christ's agony, through the running water of the Holy Spirit, are we cleansed. Christ fought the fire of sin and fought it until He Himself was totally consumed in it. He went into the fiery furnace of God's wrath, and was burnt to ashes in His work to completely extinguish it for us. Therefore we say unto our Lord with David:
Psalm 51:7 (KJV)
Purge me with hyssop, and I shall be clean: wash me, and I shall be whiter than snow.

David had killed Uriah, and his hands were stained with death. He felt condemned, and deserving of hell fire. But he remembered the times when he had returned from war, and when he had to stay outside the camp for seven days to be purified. He remembered the ashes of the heifer and the water of purification. He remembered how the heifer was killed and burnt to ashes for his sins. So he asks God to cleanse Him, knowing that God has placed his sin upon the Lord Jesus Christ. So he boldly asks for cleansing.

We ought to do the same. Our battles with sin and darkness has left us with the stains of death. But let us go aside to a desert place outside the camp, and purify ourselves with the water of purification, remembering what the Lord Jesus has done for us. He ought to have been burnt up by our sins, but He instead has been burnt for us. Let us cleanse ourselves from our battles, that we may be refreshed, so that we may return to battle with the authority of a pure conscience. Hallelujah to God who always gives us victory through Christ.