Many have repented wondering, "How will I know when I am forgiven for my sins?" They wonder whether they will feel a great burden being lifted from their shoulders; they wonder whether they should hear a voice saying, "your sins are forgiven." They may worry, because they feel nothing at all, that they are not forgiven. Therefore, the spiritual discernment of forgiveness of sins is important to everyone. Here, in this passage, we have a very descriptive and accurate term describing what it should feel like to receive a remission of sins—peace of conscience. This is the peace that the Spirit brings when a loved one passes away. It is the peace that comes to us when we search for a testimony. Note the words of the Lord to Oliver Cowdery, Verily, verily, I say unto you, if you desire a further witness, cast your mind upon the night that you cried unto me in your heart, that you might know concerning the truth of these things. Did I not speak peace to your mind concerning the matter? What greater witness can you have than from God? (DC 6:22-3, emphasis added)
Spencer W. Kimball
"The essence of the miracle of forgiveness is that is brings peace to the previously anxious, restless, frustrated, perhaps tormented soul. In a world of turmoil and contention this is indeed a priceless gift…
"Peace is the fruit of righteousness. It cannot be bought with money, and cannot be traded nor bartered. It must be earned. The wealthy often spend much of their gains in a bid for peace, only to find that it is not for sale. But the poorest as well as the richest may have it in abundance if the total price is paid. Those who abide the laws and live the Christ-like life may have peace and other kindred blessings, principal among which are exaltation and eternal life. They include also blessings for this life." (The Miracle of Forgiveness, pp. 363-4)
Harold B. Lee
"If the time comes when you have done all that you can to repent of your sins…then you will want that confirming answer as to whether or not the Lord has accepted of you. In your soul-searching, if you seek for and you find that peace of conscience by that token you may know that the Lord has accepted of your repentance. Satan would have you think otherwise and sometimes persuade you that now having made one mistake, you might go on and on with no turning back. That is one of the great falsehoods. The miracle of forgiveness is available to all of those who turn from their evil doings and return no more, because the Lord has said in a revelation to us in our days: '…go your ways and sin no more; but unto that soul who sinneth [meaning again] shall the former sins return, saith the Lord your God.' (DC 82:7) Have that in mind, all of you who may be troubled with a burden of sin." (Stand Ye in Holy Places, pp. 184-5)
Boyd K. Packer
"Often the most difficult part of repentance is to forgive yourself. Discouragement is part of that test. Do not give up. That brilliant morning will come. Then 'the peace of God which passeth…understanding' comes into your life once again. Then you like Him, will remember your sins no more. How will you know? You will know!" (Ensign, p. 208 as taken from Latter-day Commentary on the Book of Mormon compiled by K. Douglas Bassett, p. 208)