What did I do? I asked one friend to not let on that I took part in it, so as to relieve me of any appearance of guilt. Now, let me say, I wasn't guilty. At that point I had done nothing wrong, I just knew it would appear that I had to the other person. So, I manipulated the situation to 'clarify' my innocence.
What's the problem with that? A lot. I sensed it in my soul immediately.
First, my manipulation meant I didn't trust God to reveal my innocence in the situation. I trusted my own craftiness. I did not trust in God's sovereignty over all circumstances. This trust in self rather than God seems to be at the heart of a lot of my sin.
Second, I showed cowardice. Instead of being willing to face up to the situation no matter how bad it looked, and speak the truth no matter how awkward it seemed, I opted to take cover in secrecy.
Third, I encouraged my friend to lie. Though I did not ask him to lie, my manipulation led to a subtle lie on his part, that I was no doubt partly responsible for. If I had not chosen to be manipulative, there would have been no lie.
Sin is most dangerous when it looks friendly: “Sin comes to us, like Judas, with a kiss; and like a Joab, with an outstretched hand and flattering words.” (J C Ryle, Holiness)
I confessed my sin, first to God. Thank God that I have a mediator between God and man, the man Christ Jesus. Thank God that I have a Savior. I did not, indeed could not, try to earn forgiveness, rather I look to my only hope in life and death, Christ.
Then, I confessed my sin to another. This is simply a safeguard to my own heart. I looked to a trusted person and explained what I had done, without trying to defend myself.
Finally, I dealt with the situation and admitted guilt.
Why? What does all this matter? Because we love God, and sin displeases him. Because He is worth it. Because holiness matters.