This is an important question for us new covenant believers in Christ because it is about our walk with God and how victoriously we live our lives and how well we relate to other people.
About Our Walk With God
Amos wrote: “Can two walk together, unless they are agreed?” (Amos 3:3)
God has declared that He remembers our sins NO MORE because of Jesus’ perfect sacrifice at the cross. (Hebrews 8:12; 10:17, words in caps for emphasis).
So dear friends, do we agree with God? If we agree with God that He remembers our sins no more, we will not have to confess our sins to God, and we can walk with Him. But if we do not agree with God, we will find ourselves confessing our sins to Him and we will not be able to walk with Him (meaning that we will not able to follow the promptings of the Spirit accurately). (Romans 8:6)
About Our Living Lives Victoriously
“Much more those who receive abundance of grace and of the gift of righteousness will reign in life through the One, Jesus Christ.” (Romans 5:17)
We note that Paul did not write “much more those who confess their sins will reign in life”. Instead, he wrote “much more those who receive abundance of grace and of the gift of righteousness will reign in life.”
Simply put, if we are sin-conscious, we will not able to live a victorious life – it only causes us to be stuck in a rut of self-examination of our failures.
But if we are forgiven-conscious and righteousness-conscious, we will know we are accepted by God through Jesus’ sacrifice, regardless of what we do or don’t do, and we will live a victorious life, enjoying fellowship with our Abba Father who sees us righteous and holy in Christ at all times.
About How We Relate To Others
“…forgiving one another, even as God in Christ forgave you.” (Ephesians 4:32)
In the old covenant, people had to forgive others in order for God to forgive them. But in the new covenant, we forgive because God in Christ has already forgiven us. We do not need to confess our sins to be forgiven – if that were the case, then we are making our confession our Saviour.
But no, Jesus is our Saviour, not our confession of sins. It would be self-righteous for a believer to confess his/her sins in order to earn God’s approval.
In conclusion, it is not a biblical practice for new covenant believers to confess sins to God.
Common misunderstandings of the Scriptures
1 John 1:9 was written to the gnostic unbelievers, not to christians. The context tells us that if these unbelievers were to confess (“homologeo” – say the same things as God) their sins, God is faithful and just (to what His Son has done at the cross) to forgive their sins and to cleanse them from all unrighteousness. And once they are cleansed from all unrighteousness, they are no longer sinners, but righteous believers in Christ.
Last but not least, the old testament believers had to confess their sins to God because they were under law and Jesus had not yet died for the forgiveness of sins. But in the new covenant, Jesus has already died for the forgiveness of sins, so we who live in the new covenant simply need to believe we are forgiven and made righteous by His blood forever. Jesus died to save us from sin-consciousness or a guilty conscience. (Hebrews 9-10)
Whenever we fail, instead of confessing our sins (which dishonours Jesus’ perfect sacrifice), we honour Jesus’ finished work by confessing our righteousness (right standing with God) in Christ, thanking Him for Jesus’ finished work. Our life is a life of thanksgiving – “therefore by Him let us continually offer the sacrifice of praise to God, that is, the fruit of our lips, giving thanks to His name.” (Hebrews 13:15) And the Holy Spirit is pleased to convict us believers of righteousness (John 16:10), for He has come to bear witness that we are sons and daughters of God (Romans 8:16) and that God remembers our sins no more. (Hebrews 10:15-17)
(Adapted from Yahoo Answers)