Charles Hodge, Systematic Theology:  Charles Hodge, a great systematic theologian of the 19^th Century makes this statement about repentance in the Christian life:

 The declarations of Scripture, which are so abundant, that there is none righteous, no not one; that all have sinned and  come short of the glory of God; that no flesh living is just in the sight of God; and that every one must lay his hand upon his mouth, and his mouth in the dust in the sight of the infinitely holy God, who accuses his angels of folly, refer to all men without exception; to Jews and Gentiles; to the renewed and. unrenewed; to babes in Christ and to mature Christians. All feel, and all are bound to acknowledge that they are sinners whenever they present themselves before God; all know that they need constantly the intervention of Christ, and the application of his blood, to secure fellowship with the Holy One. As portrayed in Scripture, the inward life of the people of God to the end of their course in this world, is a repetition of conversion. It is a continued turning unto God; a constant renewal of confession, repentance, and faith; a dying unto sin, and living unto righteousness. This is true of all the saints, patriarchs, prophets, and apostles of whose inward experience the Bible gives us any account.

Passages which describe the Conflict between the Flesh and the Spirit.

3. More definitely is this truth taught in those passages which describe the conflict in the believer between the flesh and the Spirit. To this reference has already been made. That the seventh chapter of Paul?s Epistle to the Romans is an account of his own inward life at the time of writing that Epistle, has already, as it is believed, been sufficiently proved; and such has been the belief of the great body of evangelical Christians in all ages of the Church. If this be the correct interpretation of that passage, then it proves that Paul, at least, was not free from sin; that he had to contend with a law in his members, warring against the law of his mind; that he groaned constantly under the burden of indwelling sin. At a still later period of his life, when he was just ready to be offered up, he says to the Philippians, iii. 12?14, “Not as though I had already attained, either were already perfect: but I follow after, if that I may apprehend that for which also I am apprehended of Christ Jesus. Brethren, I count not myself to have apprehended: but this one thing I do, forgetting those things which are behind and reaching forth unto those things which are before, I press toward the mark for the prize of the high calling of God in Christ Jesus.” This is an unmistakable declaration on the part of the Apostle that even at this late period of his life he was not yet perfect; he had  not attained the end of perfect conformity to Christ, but was pressing forward, as one in a race, with all earnestness that he might reach the end of his calling. To answer this, as has been done by some distinguished advocates of perfectionism, by saying that Paul=s not being perfect, is no proof that other men may not be; is not very satisfactory.

The parallel passage in Galatians, v. 16:26, is addressed to Christians generally. It recognizes the fact that they are imperfectly sanctified; that in them the renewed principle, the Spirit as the source of spiritual life, is in conflict with the flesh, the remains of their corrupt nature. It exhorts them to mortify the mesh (not the body, but their corrupt nature), and to strive constantly to walk under the controlling influence of the Spirit. The characteristic difference between the unrenewed and the renewed is not that the former are entirely sinful, and the latter perfectly holy; but that the former are wholly under the control of their fallen nature, while the latter have the Spirit of God dwelling in them, which leads them to crucify the flesh, and to strive after complete conformity to the image of God. There was nothing in the character of the Galatian Christians to render this exhortation applicable to them alone. What the Scriptures teach concerning faith, repentance, and justification, is intended for all Christians; and so what is taught of sanctification suits the case of all believers. Indeed, if a man thinks himself perfect, and apprehends that he has already attained what his fellow believers are only striving for, a great part of the Bible must for him lose its value. What use can he make of the Psalms, the vehicle through which the people of God for millenniums have poured out their hearts? How can such a man sympathize with Ezra, Nehemiah, or any of the prophets? How strange to him must be the language of Isaiah, “Woe is me I for I am undone; because I am a man of unclean lips, and I dwell in the midst of a people of unclean lips: for mine eyes have seen the King, the Lord of hosts.”

Argument from the Lord=s Prayer.

4. Not only do the holy men of God throughout the Scriptures in coming into his presence, come with the confession of sin and imperfection, praying for mercy, not only for what they were but also for what they are, but our Lord has taught all his disciples whenever they address their Father in heaven to say, “Forgive us our trespasses.” This injunction has ever been a stumbling  block in the way of the advocates of perfection from Pelagius to the present day. It was urged by Augustine in his argument against the doctrine of his great opponent that men could be entirely free from sin in the present life. The answer given to the argument from this source has been substantially the same as that given by Pelagius. It is presented in its best form by the Rev. Richard Watson.?1 That writer says, “(1.) That it would be absurd to suppose that any person is placed under the necessity of ?trespassing,? in order that a general prayer designed for men in a mixed condition might retain its aptness to every particular case. (2.) That trespassing of every kind and degree is not supposed by this prayer to be continued, in order that it might be used always in the same import, or otherwise it might be pleaded against the renunciation of any trespass or transgression whatever. (3.) That this petition ?is still relevant to the case of the entirely sanctified and the evangelically perfect, since neither the perfection of the first man nor that of angels is in question; that is, a perfection measured by the perfect law, which in its obligations, contemplates all creatures as having sustained no injury by moral lapse, and admits, therefore, of no excuse from infirmities and mistakes of judgment; nor of any degree of obedience below that which beings created naturally perfect, were capable of rendering. There may, however, be an entire sanctification of a being rendered naturally weak and imperfect, and so liable to mistake and infirmity, as well as to defect as to the degree of that absolute obedience and service which the law of God, never bent to human weakness, demands from all. These defects, and mistakes, and infirmities, may be quite consistent with the entire sanctification of the soul and the moral maturity of a being still naturally infirm and imperfect.”