How deep is this forgiveness of sins?
Let's consider the depth of release that it accorded to two red-handed rebels, men who had prided themselves on their devotion to God, only to recognize their lost state apart from the grace of God.
Peter boasted of his love for the Lord:
"Peter said unto him, Lord, why cannot I follow thee now? I will lay down my life for thy sake.
"Jesus answered him, Wilt thou lay down thy life for my sake? Verily, verily, I say unto thee, The cock shall not crow, till thou hast denied me thrice." (John 13: 37-38)
And Peter certainly cowered and denied His Lord (cf John 18)
Jesus did restore Peter, and the forgiveness and reconciliation that Peter received from His Lord and Savior empowered him to declare the first evangelical sermon on the day of Pentecost (cf Acts 2)
What he declared to another congregation is more striking, however:
"And when Peter saw it, he answered unto the people, Ye men of Israel, why marvel ye at this? or why look ye so earnestly on us, as though by our own power or holiness we had made this man to walk?
"The God of Abraham, and of Isaac, and of Jacob, the God of our fathers, hath glorified his Son Jesus; whom ye delivered up, and denied him in the presence of Pilate, when he was determined to let him go." (Acts 3: 13-14)
Read that again. Peter had the boldness, if not the audacity, to declare the Jews listening to him that they had "delivered and denied" Jesus Christ! This uncouth fisherman, who had boasted of his love for Jesus, only to deny him three times, was now convicting others of denying Jesus Christ "the Holy One and the Just". Where else could he have drawn such confidence for himself but from the complete remission of sins which he believed and received from Jesus Christ?