It’s a little surprising that the NT word for “repent” is rarely used in the OT except with regard to God himself. In fact, metanoeo, the Greek verb translated “repent” in Acts 2:38 appears only 19 times in 18 OT verses.
Of these, 14 refer to God relenting or changing his mind. Obviously, God does not sin and therefore he cannot repent in the sense of giving up sin. Therefore, metanoeo does not necessarily refer to giving up sin.
The clearest use of metanoeo to refer to repentance in anticipation of the Kingdom is found in Isaiah —
(Isa 46:8-13 ESV) 8 “Remember this and stand firm, recall it to mind [LXX: metanoeo], you transgressors, 9 remember the former things of old; for I am God, and there is no other; I am God, and there is none like me, 10 declaring the end from the beginning and from ancient times things not yet done, saying, ‘My counsel shall stand, and I will accomplish all my purpose,’ 11 calling a bird of prey from the east, the man of my counsel from a far country. I have spoken, and I will bring it to pass; I have purposed, and I will do it.
12 “Listen to me, you stubborn of heart, you who are far from righteousness: 13 I bring near my righteousness; it is not far off, and my salvation will not delay; I will put salvation in Zion, for Israel my glory.”
The noun form is metanoia. It appears in the OT only once, and only in Proverbs, commending the wise man for his willingness to change his mind.
The concept of repentance is, of course, found in the OT–
With only a few exceptions (e.g. Jonah 3:10; Is. 19:22), repentance is associated in the OT with God’s chosen people. Thus one should understand the concept, usually expressed metaphorically by the Hebrew verb ‘to turn’ (šûḇ), to be grounded in the gracious covenant that God had previously established with Israel (Dan. 9:3–14; 2 Chr. 7:14a, 17–18; Neh. 1:5–7). Since the people who entered into this covenant were to reflect God’s nature (Lev. 19:2; 20:22–26; Deut. 10:12–13), their turning away in unbelief and unfaithfulness implies a personal rejection of him (Deut. 4:23; 11:16; 1 Sam. 15:11; 1 Kgs. 9:6; 2 Chr. 7:19, 22; Ps. 51:4; Jer. 11:10; 34:13–16). In response to the people’s sin, God is presented as similarly turning away from them, bringing about the realization of the covenant curses (e.g. Deut. 4:15–28; 30:15–20; Dan. 9:11–14). But these curses are ultimately intended to move his people to repentance once again (Deut. 4:29–30; 1 Kgs. 8:33, 48). Thus, God initiates repentance both through the call to remember the blessings of the covenant and through the outworking of his covenantal justice (see Righteousness, justice and justification) (Is. 44:22; 55:1–3; Neh. 9:26–31; Jer. 5:3; 29:10–14; 44:4–6).
Repentance therefore involves the turning away from those actions and attitudes that are offensive to God and his nature (1 Sam. 7:3; Jer. 4:1; Ezek. 14:6). It naturally includes the confession of sin, appropriately accompanied by mourning and regret (Joel 2:12–13; Jer. 3:13). Given the covenantal context, this is often expressed as ‘turning back’ to God, (which explains the frequent translation of šûḇ as ‘return’: Deut. 30:2; 2 Chr. 30:6–9; Is. 31:6; Jer. 3:22; 31:18–19; Lam. 3:40; Hos. 6:1; 14:1–2, NIV). While the condition of the heart is hardly ever explicitly discussed in the legislation governing sacrifices for sin, the implicit assumption is that the offerers have humbled their hearts before God. This is confirmed elsewhere in the OT, where a sacrifice without a contrite heart is considered to be offensive to God and even sin (Amos 4:4–6; Hos. 6:6; Pss. 40:6–8; 51:16–17; 1 Sam. 15:22; Prov. 15:8; 21:3). Conversely, true repentance generates acceptable sacrifice (Ps. 51:18–19).
The behaviour resulting from true repentance is covenant love, purity and obedience that comes from the heart (see e.g. Deut. 30:6, 8, 10). The merciful divine benefits given in response to repentance include the forgiveness (see Mercy/compassion) of sin and the restoration of the covenant relationship (Deut. 4:30–31; 2 Chr. 7:13–16; Ps. 51:7–12; Is. 55:7; Jer. 15:19–21; 32:37–41; Ezek. 18:21–23; Hos. 14:5–8; Mal. 3:7, 10–12).
“REPENTANCE,” New Dictionary of Biblical Theology, 726.
The important part of this quoted text for our present discussion is that repentance in the OT is largely about restoring right relationship with God — that is, the blessings of Deu rather than the curses — largely as a matter of national sin. To repent is to return from idolatry and to honor the commands of Deu — especially the command to love God with all your heart (Deu 10:16; 30:6).
Regarding repentance from idols, Isaiah writes,
(Isa 44:22 ESV) 22 I have blotted out your transgressions like a cloud and your sins like mist; return to me, for I have redeemed you.
Isaiah is also concerned with social justice — that is, the government being just —
(Isa 59:1-9 ESV) Behold, the LORD’s hand is not shortened, that it cannot save, or his ear dull, that it cannot hear; 2 but your iniquities have made a separation between you and your God, and your sins have hidden his face from you so that he does not hear. 3 For your hands are defiled with blood and your fingers with iniquity; your lips have spoken lies; your tongue mutters wickedness. 4 No one enters suit justly; no one goes to law honestly; they rely on empty pleas, they speak lies, they conceive mischief and give birth to iniquity. 5 They hatch adders’ eggs; they weave the spider’s web; he who eats their eggs dies, and from one that is crushed a viper is hatched. 6 Their webs will not serve as clothing; men will not cover themselves with what they make. Their works are works of iniquity, and deeds of violence are in their hands. 7 Their feet run to evil, and they are swift to shed innocent blood; their thoughts are thoughts of iniquity; desolation and destruction are in their highways. 8 The way of peace they do not know, and there is no justice in their paths; they have made their roads crooked; no one who treads on them knows peace. 9 Therefore justice is far from us, and righteousness does not overtake us; we hope for light, and behold, darkness, and for brightness, but we walk in gloom. …
(Isa 59:16-20 ESV) 16 He saw that there was no man, and wondered that there was no one to intercede; then his own arm brought him salvation, and his righteousness upheld him. 17 He put on righteousness as a breastplate, and a helmet of salvation on his head; he put on garments of vengeance for clothing, and wrapped himself in zeal as a cloak. 18 According to their deeds, so will he repay, wrath to his adversaries, repayment to his enemies; to the coastlands he will render repayment. 19 So they shall fear the name of the LORD from the west, and his glory from the rising of the sun; for he will come like a rushing stream, which the wind of the LORD drives.
20 “And a Redeemer will come to Zion, to those in Jacob who turn from transgression,” declares the LORD.
Isaiah, and many of the other prophets speak out against abuse of the court system, the taking of bribes, and even violence against oppressed people.
And as it typically the case, the prophet concludes with a promise of redemption if the people will return from their sins to YHWH.
Group sin and repentance
Now, notice that the prophets almost always speak in terms of national sin and national repentance. The account of David and Bathsheba and Psalm 51 is an obvious and very important exception, but it’s an exception. Nearly all the prophetic warnings and promises are to Israel as a nation because the Law of Moses was a covenant made with Israel as a nation.
Therefore, to say that we live in Deu 30:6 times is to say that we live during a time when God blesses Israel, a nation, by giving his Spirit to the nation so that their hearts will no longer be stubborn and they will obey his laws.
Consequently, what we see is that the Jews who reject Jesus as Messiah are still under the curses of Deu 28, and those who accept Jesus either remain a part of Israel (as a remnant of Israel) or are Gentile grafted into Israel and so become heirs of the covenant promises.
This has several important implications —
* The United States of America is not Israel. The prophetic pleas for repentance were made to Israel, the bride of God, who is now also the church, the bride of Christ. Almost all the OT warnings against a nation rebelling against God and urging the nation to repent in sackcloth — all these verses that fill up Facebook asking that the USA return to God — speak to Israel, that is, the church. Surely that somehow matters. In fact, you can make a pretty good case that much of the church is presently living in rebellion to God and sackcloth would be a pretty good response.
* The church is the Kingdom of God when thought of from this direction. It’s a nation, indeed, the kingdom promised by God through Daniel, Isaiah, and other prophets to fill the earth and defeat all other nations.
* The Jews in the Gospels and Acts would have thought in national terms. They would also have though in individual terms, but national terms would have been paramount. After all, they were in Exile because of the sins of the nation. For the Exile to end, they would have thought that the nation would have to repent, because the covenant was with the nation.
This is one reason that Paul, in Rom 11, explains that God is being true to his covenant by saving a remnant of the Jewish nation, according to prophecy — as by then it was obvious that most of genetic Israel would reject the Messiah and so remain in Exile.
Paul speaks to the Gentiles much more in individual terms, usually, because they were not yet in covenant terms as a nation. But much of the speaking in Acts to Jews is in covenant terms and therefore national terms. Not always. But usually.
* One of the difficulties we have in matching the Gospels to Jesus’ sayings in the Gospels is that the Epistles usually speak in terms of individual salvation (there are plenty of exceptions, including much of Ephesians), whereas the Gospels often speak of national salvation (with plenty of exceptions). And this means that it helps to practice thinking and reading in both national and individual terms.
* The Jews understood, of course, that the nation could be in right relationship and yet individual Jews could lose their standing with God. Election was at a national level. Israel is God’s chosen people, not each Jew and, now, not each Christian. Election surely matters, but the Jews would have considered Augustine and Calvin very confused because they failed to think in Kingdom and national terms. And their shortcomings have made American evangelical Christianity nearly 100% individualistic. We have nearly no concept of group identity — so much so that we struggle to understand the meaning of “kingdom” and even Jesus as King.
I well remember countless commenters here over the years protesting my characterizing “Christ” as “Messiah” as “King.” He may be “Lord” in the sense of “divine,” but he’s certainly not my “king”! — which is very nearly blasphemous. But you can’t combine a kingdom with radical, Western, individual autonomy. We want a Savior, not a King. But in fact, we have both. In fact, we can hardly be part of a single Kingdom if our congregations are isolated from and even in competition with each other.
* This is why Paul spoke to the Greek philosophers on Mars Hill about the necessity of repentance —
(Act 17:30-31 ESV) 30 “The times of ignorance God overlooked, but now he commands all people everywhere to repent, 31 because he has fixed a day on which he will judge the world in righteousness by a man whom he has appointed; and of this he has given assurance to all by raising him from the dead.”
The Gentiles enter on the same terms as the Jews. Both enter by repentance.
* So to return to the original question, what does “repent” mean? Well, the logically equivalent question is: what must I do to be saved? — or how do I enter the kingdom? The answer is plainly “repent” or “return to God” in the Prophets. What is it in the Gospels?