So what does it mean to repent? It means that we acknowledge our sin, ask for forgiveness from the Lord and those we may have affected, try to right the wrong, and forsake the sin by not doing it again. We also must forgive ourselves. If we do not take the opportunity in this life to take these steps, it will only be more difficult in the spirit world. We will be the same in spirit as we are now. In addition, repentance is only made possible through the infinite sacrifice of the atonement. "For behold, I, God, have suffered these things for all, that they might not suffer if they would repent." (D&C 19:16)
Alma 26:22 lists powerful blessings of repentance: "Yea, he that repenteth and exerciseth faith, and bringeth forth good works, and prayeth continually without ceasing—unto such it is given to know the mysteries of God; yea, unto such it shall be given to reveal things which never have been revealed; yea, and it shall be given unto such to bring thousands of souls to repentance, even as it has been given unto us to bring these our brethren to repentance."
Repentance not only brings us wisdom and knowledge that can only be revealed through the Holy Ghost, but also leads us to peace and happiness, which also come through the Spirit.
"...the remission of sins bringeth meekness, and lowliness of heart; and because of meekness and lowliness of heart cometh the visitation of the Holy Ghost, which Comforter filleth with hope and perfect love, which love endureth by diligence unto prayer, until the end shall come, when all the saints shall dwell with God." (Moroni 8:26)