Biblical and Book of Mormon prophets taught repentance as the Lord’s way of changing our behavior.
Repentance is Necessary
The scriptures clearly teach that repentance is necessary. Jesus taught the Jews that they must repent.
I tell you, Nay: but, except ye repent, ye shall all likewise perish. (Luke 13:3)
In addition, he taught the Nephites that he came to earth as the Messiah to get people to repent.
Listen to the words of Christ, your Redeemer, your Lord and your God. Behold, I came into the world not to call the righteous but sinners to repentance; the whole need no physician, but they that are sick;… (Moroni 8:8)
On the Day of Pentecost, the Apostle Peter told those who listened to his message to repent
Then Peter said unto them, repent, and be baptized everyone of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost. (Acts 2:38)
Repentance is necessary, Peter said, if our sins are to be forgiven.
Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord; (Acts 3:19)
The Nephites were also taught that everyone must repent. Jacob said the following.
And he commandeth all men that they must repent, and be baptized in his name, having perfect faith in the Holy One of Israel, or they cannot be saved in the kingdom of God.
And if they will not repent and believe in his name, and be baptized in his name, and endure to the end, they must be damned; for the Lord God, the Holy One of Israel, has spoken it. (2 Nephi 9:23-24)
Nephi taught that not only must we repent ourselves, but we should do what we can to persuade others to repent.
Hath he commanded any that they should not partake of his salvation? Behold I say unto you, Nay; but he hath given it free for all men; and he hath commanded his people that they should persuade all men to repentance. (2 Nephi 27:27)
King Benjamin taught repentance.
And moreover, I say unto you, that the time shall come when the knowledge of the Savior shall spread throughout every nation, kindred, tongue, and people.
And behold, when that time cometh, none shall be found blameless before God, except it be little children, only through repentance and faith on the name of the Lord God Omnipotent. (Mosiah 3:20-21)
Benjamin went on to say that repentance is avoiding sin and asking God for forgiveness; he stressed we should not only know what repentance is, but we should do it!
And again, believe that ye must repent of your sins and forsake them, and humble yourselves before God; and ask in sincerity of heart that he would forgive you; and now, if you believe all these things see that ye do them. (Mosiah 4:10)
Alma taught that repentance is absolutely necessary.
Behold, now I say unto you that he commandeth you to repent; and except ye repent, ye can in nowise inherit the kingdom of God. But behold, this is not all–he has commanded you to repent, or he will utterly destroy you from off the face of the earth; yea, he will visit you in his anger, and in his fierce anger he will not turn away. (Alma 9:12)
Alma’s missionary companion, Amulek, taught that we should repent now and not wait until we are on our death-bed.
Yea, I would that ye would come forth and harden not your hearts any longer; for behold, now is the time and the day of your salvation; and therefore, if ye will repent and harden not your hearts, immediately shall the great plan of redemption be brought about unto you.
For behold, this life is the time for men to prepare to meet God; yea, behold the day of this life is the day for men to perform their labors.
And now, as I said unto you before, as ye have had so many witnesses, therefore, I beseech of you that ye do not procrastinate the day of your repentance until the end; for after this day of life, which is given us to prepare for eternity, behold, if we do not improve our time while in this life, then cometh the night of darkness wherein there can be no labor performed.
Ye cannot say, when ye are brought to that awful crisis, that I will repent, that I will return to my God. Nay, ye cannot say this; for that same spirit with which ye go out of this life, that same spirit will have power to possess your body in that eternal world.
For behold, if ye have procrastinated the day of your repentance even until death, behold, ye have become subjected to the spirit of the devil, and he doth seal you his; therefore, the Spirit of the Lord hath withdrawn from you, and hath no place in you, and the devil hath all power over you; and this is the final state of the wicked. (Alma 34:31-35, emphasis added)
Amulek is saying that when we die, we will have the same personality and attitudes [spirit] in the next life that we have here, implying that if we would not repent in this life we will not repent in the next life; thus we should do it now! Furthermore, he said those who refuse to repent in this life become subject to Satan and lose the companionship of the Holy Ghost.
From another viewpoint, we can clearly understand why repentance is necessary. Jesus, in describing the latter days, said the following.
And many false prophets shall arise, and shall deceive many.
And because iniquity shall abound, the love of many shall wax cold.
But he that shall endure unto the end, the same shall be saved. (Matthew 24:11-13)
Jesus is saying that it is not sufficient to accept him and then sit back and say, “I’m saved”. As long as we live and have agency, we can choose evil instead of good. Through committing sins we become separated from God and let our love of God “wax cold”. We must continue to be faithful to God (endure unto the end) if we are to be saved.
Steps of Repentance
In rebuking Simon for trying to buy the Priesthood, Peter explained that repentance must be used with prayer to God.
Repent therefore of this thy wickedness, and pray God, if perhaps the thought of thine heart may be forgiven thee. (Acts 8:22)
Notice the order of Peter’s rebuke: repentance, prayer, forgiveness. That is the order we must follow if we are to be forgiven.
The scriptures teach we must follow certain steps if we are to truly repent. First, we must recognize and admit to ourselves we have sinned, not just sinning in general but specific sins, specific acts.
If we say that we have no sin, we deceive ourselves, and the truth is not in us. (1 John 1:8)
Next, we must confess our particular sins to God and to those against whom we have sinned.
If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness. (1 John 1:9)
Third, we must have true sorrow for our actions. We must sincerely wish we had not done those particular things. We must have sorrow that leads us to repentance.
Now I rejoice, not that ye were made sorry, but that ye sorrowed to repentance: for ye were made sorry after a godly manner, that ye might receive damage by us in nothing.
For godly sorrow worketh repentance to salvation not to be repented of: but the sorrow of the world worketh death. (2 Corinthians 7:9-10)
Fourth, we must make restitution, in so far as is possible, to those whom we have harmed.
And if it be stolen from him, he shall make restitution unto the owner thereof. (Exodus 22:12)
Fifth, we must change our lives such that we do not repeat the sins.
Wherefore putting away lying, speak every man truth with his neighbour: for we are members one of another.
Be ye angry, and sin not; let not the sun go down upon your wrath:
Neither give place to the devil.
Let him that stole steal no more: but rather let him labour, working with his hands the thing which is good, that he may have to give to him that needeth. (Ephesians 4:25-28)
And last, we must forgive those whom we have sinned against and those who sin against us. Forgiving those who have hurt us does not imply that we condone their acts. It does not imply that they should escape being required by justice to account for their actions. It does mean that we do not hold bitterness in our hearts towards them. It does mean that we love them as children of God. It does mean that we will allow the law of our nation and in the final sense God to be their judge.
Let all bitterness, and wrath, and anger, and clamour, and evil speaking, be put away from you, with all malice:
And be ye kind one to another, tenderhearted, forgiving one another, even as God for Christ’s sake hath forgiven you. (Ephesians 4:31-32)
We see that repentance is the way in which we change our lives to be like the Savior. This was clearly taught by Jesus in the Sermon on the Mount, a sermon in which he taught we should rise above the carnal, physical world and live a higher, spiritual law. As we read the words of Jesus, we realize that we have come short of the goals given by the Savior. We realize that we need to change our lives through repentance.
Purpose of Repentance
Nephi taught that those who believe in Jesus and repent from their sins are accepted by God.
For Behold, I say unto you that as many of the Gentiles as will repent are the covenant people of the Lord; and as many of the Jews as will not repent shall be cast off; for the Lord covenanteth with none save it be with them that repent and believe in his Son, who is the Holy One of Israel. (2 Nephi 30:2)
The Lord revealed to Alma the rewards that come to those who repent.
Wherefore I say unto you, Go; and whosoever transgresseth against me, him shall ye judge according to the sins which he has committed; and if he confess his sins before thee and me, and repenteth in the sincerity of his heart, him shall ye forgive, and I will forgive him also. (Mosiah 26:29)
What greater reward can we have than forgiveness from God!
In revelation to Joseph Smith, the Lord explained that repentance is the gateway by which his atonement comes into our lives and cleanses us.
For behold, I, God, have suffered these things for all, that they might not suffer if they would repent;
But if they would not repent they must suffer even as I; (D&C 19:16-17)
If we repent, the Savior allows his atonement, his suffering 2000 years ago, to cleanse us, and the justice of God is satisfied. However, if we do not repent, then we must satisfy the justice of God by suffering for our sins because Jesus will not allow his suffering to satisfy justice. After we have suffered for our sins, Jesus allows his atonement to cleanse us.