This is one of a very numerous class of passages which summon sinners to the duty of moral purification, of thorough and complete reformation of character (Jer. iv. 14; James iv. 8; Jer. xviii. 11; Ezek. xviii. 30-32, &c.) These passages are very clear and emphatic, but they seem to be in opposition to others which assert man's natural inability to do anything that is good (Matt vii. 18; Rom. vii. 18-23; John xv. 5), with others which teach that repentance is a Divine gift (Acts v. 31; 2 Tim. ii. 25), and with those which teach that sanctification is the work of the Holy Spirit (1 Cor. vi. 11, &c.) The opposition is only apparent.[1] Every Divine command really involves a promise of the grace necessary for its accomplishment, and God is ever ready to work with and in us "to will and to do of His good pleasure."[2] Fallen as we are, we yet retain the power of responding to or of rejecting His admonitions; if we respond to them, there instantly begins to flow into our souls that which will enable us to accomplish everything that God has required (Phil. iv. 13). Three great questions--+I. Why must we cleanse ourselves from evil?+ 1. _Because sin renders us offensive to God._ It is in itself repulsive to Him, just as immodesty in all its forms and in every degree is repulsive to a virtuous woman (Hab. i. 13; Prov. xxxi. 10-31). 2. _Because it is destructive to ourselves._ In physical matters dirt and disease are inseparable, and so they are in spiritual. Moral pollution leads to moral decay. Sin is a leprosy that eats away all the finer faculties of the soul. 3. _Because it renders us dangerous to our fellow-men._ In the measure that we are corrupt, we shall corrupt others. There is a terrible contagiousness in iniquity (Prov. xxii. 24, 25; Rev. xviii. 4). A sinner is a walking pestilence. And 4. The special lesson of our text in its connection--_Because otherwise access to the throne of grace will be closed against us._ If it be not so with us now, yet there will come a season when it will be supremely important to us that God should hear our prayers (a time of great trouble, or the hour of death), and how awful will be our condition if God should then turn a deaf ear to us! But this is the doom of obdurate sinners (ver. 15; Jer. xi. 14, &c.) +II. How may we cleanse ourselves from evil?+ 1. _By resolutely putting off our old evil habits._ This is what Isaiah exhorted the Jews to do (vers. 16, 17). Similar exhortations occur in the New Testament (Eph. iv. 25-29; Heb. xii. 1). Begin with the faults of which you are most conscious.[3] Begin and continue the great task of moral reformation in humble dependence upon God. 2. _By prayer._ In earnest communion with God our views of duty and purity receive a marvellous elevation, and we catch the inspiration of the Divine character, so that iniquity, instead of being attractive, becomes hateful to us also.[4] 3. _By humble but resolute endeavours to copy the example of our Lord Jesus Christ._ 4.