Consider:
I. That part of the exhortation which requires the destruction of evil: "Let us cleanse ourselves from all filthiness of the flesh and spirit." By filthiness is meant moral pollution of any kind. It denotes not exclusively or especially any particular sin, but sin as such everything which renders the character loathsome in God's sight. (2) The words "flesh and spirit" we understand as denoting the seat of the sin. Filthiness of the flesh we take to be sin in its outward manifestation; filthiness of the spirit, sin in its internal emotions. (3) The cleansing required extends to both. (4) The extent of the cleansing required is shown by the use of the word all.He who would taste Christianity's joys and reap her rewards must have no favourite sins. He must cleanse himself from all filthiness of the flesh and spirit. (5) The exhortation of the text shows us that, while God is the sanctifier of His people, there is an important sense in which we must sanctify ourselves.
II. That part of the exhortation which enjoins the cultivation of perfect holiness. Trusting in Christ for sanctification no less than for forgiveness is our first duty; for until we trust in Him and are united to Him by a living faith, no effort we may make in order to sanctify ourselves will be of any avail. The danger against which we need to be on our guard is that, instead of resting in Christ for sanctification, we should be persuading ourselves that we are sanctified, when it is only too manifest that we are resting, not in Christ, but in our own fancies about Christ resting not for but without sanctification, and thereby jeopardising our own souls.
W. Landels, Christian World Pulpit,vol. vii., p. 328.
References: 2 Corinthians 7:1. R. W. Dale, Christian World Pulpit,vol. xxxv., p. 81; F. W. Robertson, Lectures on Corinthians,p. 360. 2 Corinthians 7:2-8. Ibid.,p. 365. 2 Corinthians 7:4. Homiletic Quarterly,vol. i., p. 265. 2 Corinthians 7:6. S. Martin, Westminster Chapel Sermons,vol. iii., p. 213; Spurgeon, Morning by Morning,p. 51. 2 Corinthians 7:9; 2 Corinthians 7:10. F. W. Robertson, Lectures on Corinthians,p. 372; Ibid., Sermons,3rd series, p. 104.