I was recently thinking back to a time when I reviewed an old exam for teaching purposes. I recall being disappointed in some of the comments I received from the grader on a few of my answers when I got the test back, and in reality I was angry because I thought his grading was biased because I was a woman. He made what I thought were nitpicky comments about various things and required that I rewrite several of my answers. I did as he asked and when I received it back for the second time I was indignant. His responses were again- nitpicky. By the third rewrite on some of these questions I was very angry. I never met the grader in person, and he was someone I had only heard in recorded lectures. I had formed a negative opinion of him from the lectures, and the exam commentary only furthered my dislike of him.
Years went by and had no reason  to look at those exams until I needed to use them to teach something. When I re-read the comments (now many years old) I was shocked at the level of anger and bitterness I felt rise up in me and heard in the words I heard come out of my mouth.
Why I was shocked I don’t know- I clearly recalled being very angry at the time! What I couldn’t understand was how I could experience that level of anger and bitterness all those years later, and wondered where on earth did all that anger come from in the present day?
The simple, and truthful answer is that it had been stored up in my heart for all those years because I never dealt with it biblically. I made a decision at the time to file away my thoughts and beliefs and feelings about this along with those exams and that day they came back to defile many. Hebrews 12:15 says, “See to it that no one comes short of the grace of God; that no root of bitterness springing up causes trouble, and by it many be defiled”
One evening I shared my thoughts about the person who graded my exam  with a small group of people and the bitterness in my heart was completely apparent. My grumbling and complaining was contagious as a few other people began to talk about “unfair” grades they received on papers in the past. It was amazing to me to see the level of emotion rising in the room as several of us talked unkindly about those situations. My bitterness was the catalyst to their self-disclosure. I was rejoicing as I listened to them because I felt vindicated and righteous for being angry.
It didn’t take long however for the gentle conviction of the Holy Spirit to affect my heart. As I left the building that night, I realized that I had been holding all that bitterness and anger in my heart for all those years! I replayed in my mind what that had done to the group I was with and I was very sad.
As I continued to think about it on the drive home, I realized that I was bitter toward this man for doing his job! I had to ask myself what his goal was. The reality is that he was to see to it that I was proficient in the skills I was being tested on. I had to ask myself if it was personal- were his comments and corrections aimed at my character or at my person hood? No they were not. This man had never laid eyes on me, all he knew of me was my test and the brief disclosures I was to make on an introductory cover sheet. I had to ask myself if I was judging him unjustly and my only conclusion was, yes. I did not like his opinions on my test answers and I took it personally. My pride was wounded all those years ago and I never dealt with it biblically.
Obviously I had to deal with this right away! It was too late that night to speak with those I had affected in the group, so I had a week to contemplate and think on the whole thing. I know and teach that the scope of confession is as great as the scope of offense so I knew I needed to confess my bitterness to my friends and ask their forgiveness for venting my sinful heart to them, and for leading a few of them to sin by my poor example. But first, I had to confess my bitterness and anger to God. It was not as though God didn’t already know about this…He was been aware of my heart and what it contains. Why God allowed me to go along that way for several years is a question I do not have the answer to, but I am thankful that I saw it and dealt with it once for all.
As I examined my heart I realized that not only did I harbor bitterness toward this man for his criticism of my answers, I was judging him in my heart as well. I was assigning malicious intent to his actions, and judging his motives.
I was deeply grieved at my sin. I admitted to God that I had been carrying around this bitterness for a long time, that I had judged this man unjustly, that my pride had been affected, and that I was totally self-righteous in my thinking.
The next step was to confess to that group of people what the Holy Spirit revealed to me (bitterness, pride, self-righteousness) and to ask their forgiveness for my grumbling and complaining as well as for encouraging them to sin as a result of my displayed anger and bitterness.
God is incredible. He is so gracious and so gentle in His dealings with me! I did not arrive at these conclusions through fear or intimidation, through threats or a verbal or spiritual clubbing. I came to understand and believe the truth about this sin in my heart in a gentle and convicting way. I simply held my words, thoughts, reactions, feelings and desires up against the Word of God, and the character of the Lord Jesus Christ and realized I was not bringing Him glory by any of it.
You may want to believe that you can “gloss over” sin and leave it in the past without dealing with it biblically through confession and repentance, but that is not so! My sin was content to stay buried in my heart and eat away at me directly and indirectly. Sin is insidious and hates exposure. 
The more you pursue holiness, and the more you desire to glorify God the more you can be certain God will clean out those little locked boxes in your heart. His desire is that you and I be holy as He is holy, and He will use all the means at His disposal to complete the work that He has started (Phil.2:13). God is completely faithful and He will not leave you or I mid-stream, He is intent on our being conformed to the image and likeness of Christ in total. Rejoice in this, and be glad!