In the New Testament, the word translated as 'repentance' is the Greek word μετάνοια (metanoia), "after/behind one's mind", which is a compound word of the preposition 'meta' (after, with), and the verb 'noeo' (to perceive, to think, the result of perceiving or observing). In this compound word the preposition combines the two meanings of time and change, which may be denoted by 'after' and 'different'; so that the whole compound means: 'to think differently after'. Metanoia is therefore primarily an after-thought, different from the former thought; a change of mind accompanied by regret and change of conduct, "change of mind and heart", or, "change of consciousness". One of the key descriptions of repentance in the New Testament is the parable of the prodigal son found in the Gospel of Luke 15 beginning at verse 11.
The full meaning of repentance in the Hebrew Bible is indicated in the Hebrew term teshuvah (lit. "return"). This implies: (1) Transgression and sin are the natural and inevitable consequence of man's straying from God and His laws (comp. Deut. 11:26-28; Isa. 1:4; Jer. 2:13, 16:11; Ezek. 18:30). (2) It is man's destiny, and therefore his duty, to be with God as God is with him. (3) It is within the power of every man to redeem himself from sin by resolutely breaking away from it and turning to God. God's loving-kindness is also extended to the returning sinner. "Let the wicked forsake his way, and the unrighteous man his thoughts: and let him return unto the Lord, and he will have mercy upon him; and to our God, for he will abundantly pardon" (Isa. 55:7) (4) Because "there is not a just man upon earth, that does good, and sins not" (Eccl. 7:20; I Kings 8:46), every mortal stands in need of this insistence on his "return" to God.
The Torah (five books of Moses) distinguishes between offenses against God and offenses against man. In the first case the manifestation of repentance consists in: (1) Confession of one's sin before God (Lev. 5:5; Num. 5:7), the essential part being a solemn promise and firm resolve not to commit the same sin again. (2) Making certain prescribed offerings (Lev. 5:1-20). Offenses against man require, in addition to confession and sacrifice, restitution in full of whatever has been wrongfully obtained or withheld from one's fellow man, with one-fifth of its value added thereto (Lev. 5:20-26). If the wronged man has died, restitution must be made to his heir; if he has no heir, it must be given to the priest who officiates at the sacrifice made for the remission of the sin (Num. 5:7-9).
The Prophets disparaged all such outer manifestations of repentance, insisting rather on a complete change of the sinner's mental and spiritual attitude. They demanded a regeneration of the heart, i.e., a determined turning from sin and returning to God by striving after righteousness. "O Israel, return unto the Lord thy God; for thou hast fallen by thine iniquity. Take with you words, and return unto the Lord: say unto him, Take away all iniquity, and accept us graciously: so will we render as bullocks the offerings of our lips" (Hosea 14:1-2, Hebrew). "Rend your heart, and not your garments, and turn unto the Lord your God: for he is gracious and full of compassion, slow to anger and plenteous in mercy, and repenteth him of the evil" (Joel 2:13).
Repentance brings pardon and forgiveness of sin (Isaiah 55:7). Outside of repentance the prophets and apostles know of no way of securing pardon. No sacrifices, nor religious ceremonies can secure it. Not that repentance merits forgiveness, but it is a condition of it. Repentance qualifies a man for a pardon, but it does not entitle him to it.
"The Holy One, blessed be His name, said to Elijah, 'Behold, the precious gift which I have bestowed on my world: though a man sins again and again, but returns in penitence, I will receive him'" (Jerusalem Talmud Sanhedrin 28b).
"Great is repentance: it brings healing into the world"; "it reaches to the throne of God" (Hosea 14:2, 5); "it brings redemption" (Isiah 59:20); "it prolongs man's life" (Ezekiel 18:21; Talmud Yoma 86a).
"Repentance and works of charity are man's intercessors before God's throne" (Talmud Shabbath 32a). Sincere repentance is equivalent to the rebuilding of the Temple, the restoration of the altar, and the offering of all the sacrifices (Pesiqta, ed. Buber, 25:158; Midrash Leviticus Rabbah 7; Talmud Sanhedrin 43b).
Sincere repentance is manifested when the same temptation to sin, under the same conditions, is ever after resolutely resisted (Talmud Yoma 86b; Mishneh Torah Teshuva 2:1-2). "He that confesses his sin and still clings to it is likened to a man that holds in his hand a defiling object; though he batheth in all the waters of the world he is not cleansed; but the moment he casteth the defiling object from him a single bath will cleanse him, as it is said (Proverbs 28:13): 'Whosoever confesses and forsakes them [his sins] shall have mercy'" (Talmud Taanith 16a; Mishneh Torah Teshuva 2:3).
Repentance and the Day of Atonement only absolve one from sins committed against God; from sins against another person they absolve only when restitution has been made and the pardon of the offended party has been obtained (Talmud Yoma 87a; Mishneh Torah Teshuva2:9).
No one need despair on account of his or her sins, for every penitent sinner is graciously received by God. (Jeremiah 31:9).
Jewish doctrine holds that it is never too late, even on the day of death, to return to God with sincere repentance for "as the sea is always open for every one who wishes to cleanse himself, so are the gates of repentance always open to the sinner" (Pesiqta., ed. Buber, xxv. 157; Midrash Deuteronomy Rabbah ii.; Midrash Psalms lxiii.), and the hand of God is continually stretched out to receive him (Talmud Pesachim 119a; Deuteronomy Rabbah ii). One view in the Talmud holds that a repentant sinner attains a more exalted spiritual eminence than one who has never sinned (Talmud Berakhoth 34b.) It is a sin to taunt a repentant sinner by recalling their former sinful ways (Talmud Bava Metsia 58b; Mishneh Torah Teshuva 8:8).
Repentance occupies a prominent position in all the ethical writings of the Middle Ages. Bahya ibn Paquda devotes a special section to it in his 'Hovot ha-Levavot", "Gate of Repentance." Maimonides devotes the last section of "Sefer ha-Madda'" in his Mishneh Torah to the subject. One of the most significant medieval works on Repentance is "Shaarei Teshuva," the "Gates of Repentance." Written by Rabbeinu Yona of Gerona, it is a work entirely on repentance.
When Jesus sent forth messengers to proclaim his gospel, he commanded them to preach repentance (Luke 24:47; Mark 6:12). Teachings on repentance are found in the New Testament in Peter, (Acts 2:38); Paul, (Acts 20:21). God wants everyone to repent (2 Pet. 3:9; Acts 17:30). Indeed, failure on the part of man to heed God's call to repentance means that he shall utterly perish (Luke 13:3).
The constant references to repentance in Peter's preaching to his fellow countrymen in the early part of the book of Acts may indicate an exceptional need for repentance amongst those who had recently been party to the crucifixion of Christ. Paul is emphatic that change take place amongst those who he taught (see the Bible references to "turning to a true and living God"). This aversion to the Greek or idolatrous lifestyle may have come from the intense patriotism to Jewish ideals held by the well educated former Pharisee .
Saint Isaac of Syria said, "This life has been given to you for repentance. Do not waste it on vain pursuits."
"In the first place, when we call repentance “a conversion of the life to God, we require a transformation, not only in the external actions, but in the soul itself; which, after having put off the old nature, should produce the fruits of actions corresponding to its renovation. . . .In the second place, we represented repentance as proceeding from a serious fear of God. For before the mind of a sinner can be inclined to repentance, it must be excited by the knowledge of the Divine judgment. . . .
"It remains for us, in the third place, to explain our position, that repentance consists of two parts—the mortification of the flesh and the vivification of the spirit. . . . Both these branches of repentance effects our participation of Christ. For if we truly partake of his death, our old man is crucified by its power, and the body of sin expires, so that the corruption of our former nature loses all its vigor. . . .If we are partakers of his resurrection, we are raised by it to a newness of life, which corresponds with the righteousness of God." [Quotes from A Compend of the Institutes of the Christian Religion by John Calvin edited by Hugh T. Kerr, The Westminster Press-Philadelphia 1939.]
The Hebrew equivalent is strong as well, and it means to pant, to sigh, or to moan. So the publican "beat upon his breast," indicating sorrow of heart. See also Psalms 38:18.
There must be confession to man also in so far as man has been wronged in and by our sin (); James 5:16).
In this view, people are called upon to repent in order that we may feel our own inability to do so, and consequently be thrown upon God and petition Him to perform this work of grace in our hearts. Many church fathers have made reference to it as the "gift of repentance" or as the "gift of tears".
God calls all to repent through the hearing of the Gospel. God grants total repentance as each individual responds to repentance through faith in the expiating sacrifice of Jesus for all sin. "So then faith cometh by hearing, and hearing by the word of God." (Romans 10:17).
Repentance is given before anything else by definition. One cannot show true change in his life before he himself has changed [repented] to bring about manifestations of that change/repentance.
Rev. 3:19; Heb. 12:6, 10-11. The chastisements of God are sometimes for the purpose of bringing His wandering children back to repentance.
2 Tim. 2:24-25. God often uses the loving, Christian reproof of a brother to be the means of bringing us back to God.
According to The Church of Jesus Christ of Latter Day Saints, repentance denotes a change of mind, i.e., a fresh view about God, about oneself, and about the world. Since humans are born into conditions of mortality, repentance comes to mean a turning of the heart and will to God, and a renunciation of sin. Without repentance, there can be no progress in the things of the soul’s salvation, for all accountable persons are stained by sin, and must be cleansed in order to enter the kingdom of heaven according to LDS doctrine. Repentance is not optional for salvation; it is a commandment of God according to the Doctrines & Covenants of the LDS Church (D&C 18: 9-22; D&C 20: 29; D&C 133: 16). The preaching of repentance by John the Baptist formed the basis for this doctrine. See Matt. 3: 2; Matt. 4: 17; Mark 1: 4, 15; Mark 2: 17; Luke 3: 3,8; Acts 2: 38; Acts 3: 19; Acts 8: 22; Rom. 13: 11-14; James 5: 1-6; Rev. 2: 5, 16; Rev. 3: 3, 19; cf. Isa. 1: 16-20; Jonah 3: 5-10; Jer. 3 - 5; Jer. 26; Ezek. 18: 19-31; Ezek. 33: 7-20; Hosea 13: 14; Hosea 14; Joel 1: 8; Joel 2; Zeph. 2; Zech. 1; Mal. 1 - 4.