I really appreciate King David's confession in Psalm 51 which I will use to answer...
How would you define "confession"?
1 Be gracious to me, O God, according to Your lovingkindness;
According to the greatness of Your compassion blot out my transgressions.
3 For I know my transgressions,
And my sin is ever before me.
4 Against You, You only, I have sinned
And done what is evil in Your sight,
So that You are justified when You speak
And blameless when You judge.
Why is confessing our sins so important?
5 Behold, I was brought forth in iniquity,
And in sin my mother conceived me.
6 Behold, You desire truth in the innermost being,
And in the hidden part You will make me know wisdom.
What happens to us if we stop confessing our sins?
consider the opposite of the following passages:
7 Purify me with hyssop, and I shall be clean;
Wash me, and I shall be whiter than snow.
8 Make me to hear joy and gladness,
Let the bones which You have broken rejoice.
9 Hide Your face from my sins
And blot out all my iniquities.
10 Create in me a clean heart, O God,
And renew a steadfast spirit within me.
11 Do not cast me away from Your presence
And do not take Your Holy Spirit from me.
12 Restore to me the joy of Your salvation
And sustain me with a willing spirit.
What are the promises given to us if we do confess our sins?
now, consider them again...
7 Purify me with hyssop, and I shall be clean;
Wash me, and I shall be whiter than snow.
8 Make me to hear joy and gladness,
Let the bones which You have broken rejoice.
9 Hide Your face from my sins
And blot out all my iniquities.
10 Create in me a clean heart, O God,
And renew a steadfast spirit within me.
11 Do not cast me away from Your presence
And do not take Your Holy Spirit from me.
12 Restore to me the joy of Your salvation
And sustain me with a willing spirit.
13 Then I will teach transgressors Your ways,
And sinners will be converted to You.
14 Deliver me from bloodguiltiness, O God, the God of my salvation;
Then my tongue will joyfully sing of Your righteousness.
15 O Lord, open my lips,
That my mouth may declare Your praise.