Our Conscience Is God The Holy Spirit Convicting Each One Of Us Of Our Sins
After Jesus was baptised by his cousin, John the Baptist, "The Holy Spirit descended in bodily form like a dove upon Him, and a voice came from Heaven which said, "You are My beloved Son; in You I am well pleased," Luke 3:22
A dove in the natural world is a very gentle bird, and will fly away if disturbed. All humans have a conscience, which pure science can never explain. Our conscience is God the Holy Spirit, speaking quietly to each of us throughout our lives. If we persist in sin, the Holy Spirit, like a dove, will depart. This is how some people seem to become so insensitive to sin in their lives.
In John 8:7-9 a woman was caught in adultery, The Jews were about to execute the woman, and Jesus said, "He who is without sin among you, let him throw a stone at her first. And again He stooped down and wrote on the ground. Then those who heard it, being convicted by their conscience, went out one by one." Note that the onlookers were "convicted by their conscience."
Later Jesus said, at the Last Supper, that the Comforter, the Holy Spirit, would convict everyone of sin: "And when He (the Holy Spirit) has come, He will convict the world of sin, and of righteousness, and of judgement," John 16:8.
The voice of the Holy Spirit convicts us of sin
The voice of the Holy Spirit is gentle, like a dove. His voice is identical to your conscience, since God speaks to us using our conscience. When you pray, you might like to approach God like a little child, and ask Him to show you the sin in your life. He will.
You will hear the quiet voice of the Holy Spirit revealing sin in your life, and those things in your life He wants you to stop doing. He may reveal things from many years ago, or things about your present lifestyle He wants you to change.
He will also reveal to you those people who you need to forgive. You must forgive anyone who has sinned against you, or your family, in any way. Jesus said, in Matthew 6:15, 'If you do not forgive men their trespasses, neither will your Father forgive your trespasses.' According to Jesus, you must therefore forgive everyone, or God will not forgive you.