Repentance causes a change in the affections, which move under the will as the commander-in-chief. It metamorphoses the affections. It turns rejoicing in sin into sorrowing for sin; it turns boldness in sin into holy shame; it turns the love of sin into hatred.Ten Commandments, 207
Surely no rebel can expect the King to pardon his treason while he remains in open revolt. No one can be so foolish as to imagine that the Judge of all the earth will put away our sins if we refuse to put them away ourselves. All of Grace (116)
The nature of true repentance is clearly and unmistakably laid down in holy Scripture.
It begins with knowledge of sin.
It goes on to work sorrow for sin.
It leads to confession of sin before God.
It shows itself before man, by a thorough breaking off from sin.
It results in producing a habit of deep hatred for all sin.
Above all, it is inseparably connected with lively faith in the Lord Jesus Christ. Repentance like this is the characteristic of all true Christians.Gospel of Luke Commentary
we have to remember that genuine repentance is more fundamentally a matter of the heart's attitude toward sin than it is a mere change of behaviour. What is the Gospel?(81)
When repentance is attributed to God it noteth only the alteration of things and actions done by him, and no change of his purpose and secret decree, which is immutable. Repentance with man is the changing of his will; repentance with God is the willing of a change.
Faith is not bare knowledge or passive persuasion but the
embrace of Christ by the heart, resulting in personal knowledge of God.
The heart must therefore be prepared by the law awakening the sinner
to his need of Christ. The law beats on the stony heart as a hammer to
smooth its surface before God writes His Word upon it. Though some
men called this repentance, Calvin preferred to think of it as preparation
for faith, which in turn leads to true repentance.
The New Testament word for "repentance" means changing one's mind so that one's views, values, goals, and ways are changed and one's whole life is lived differently. The change is radical, both inwardly and outwardly; mind and judgment, will and affections, behavior and lifestyle, motives and purposes, are all involved. Repenting means starting to live a new life.Concise Theology Section 60
It must be stressed that the moral law, as crystallized in the Decalogue and opened up in the ethical teaching of both Testaments, is one coherent law, given to be a code of practice for God's people in every age. In addition, repentance means resolving henceforth to seek God's help in keeping that law. The Spirit is given to empower law-keeping and make us more and more like Christ, the archetypal law-keeper (Matt. 5: 17). This law-keeping is in fact the fulfilling of our human nature, and Scripture holds out no hope of salvation for any who, whatever their profession of faith, do not seek to turn from sin to righteousness (1 Cor. 6:9-11; Rev. 21:8).Concise Theology
There is an eternal difference between regret and repentance. Regret feels bad about past sins. Repentance turns away from past sins. Regret looks to our own circumstances. Repentance looks to God. Most of us are content with regret. We just want to feel bad for awhile, have a good cry, enjoy the cathartic experience, bewail our sin, and talk about how sorry we are. But we don't want to change. We don't want to deal with God.
The Christian religion is the religion of sinners, of such as have sinned, and in whom sin in some measure still dwells.
The Christian life is a life of continued repentance, humiliation for and mortification of sin, of continual faith in, thankfulness for, and love to the Redeemer, and hopeful joyful expectation of a day of glorious redemption, in which the believer shall be fully and finally acquitted, and sin abolished for ever.
Let us beware of any repentance, falsely so called, which is not of this character. Action is the very life of "repentance unto salvation." Feelings, and tears, and remorse, and wishes, and resolutions, are all useless, until they are accompanied by action and a change of life. In fact they are worse than useless. Insensibly they sear the conscience and harden the heart.
J. C. Ryle. Expository Thoughts on the Gospels
Repentance is a heartfelt sorrow for sin, a renouncing of it, and a sincere commitment to forsake it and walk in obedience to Christ.Systematic Theology
Repentance unto life is a saving grace, whereby a sinner, out of an apprehension of his sin, and apprehension of the mercy of God in Christ, does, with grief and hatred of his sin, turn from it, unto God, with full purpose of, and endeavour after, new obedience.Westminster Shorter Catechism, Question 87
Repentance means turning from as much as you know of your sin to give as much as you know of yourself to as much as you know of your God, and as our knowledge grows at these three points so our practice of repentance has to be enlarged.