Who is your equilibrium?
A person's centeredness is a powerful thing. Everything they do flows from that place. If someone is angry or agitated, everything they do will be off. If they are self-centered, they will be shallow and hard-pressed to offer true compassion to a hurting world.
Peter went through a trying time. Because of his natural confidence and inclination to leadership, he seems to have taken point at the head of Jesus' entourage. Nothing wrong with an assertive type-A personality, but in God's Kingdom that attitude would necessarily need to be tempered with patience, gentleness, humility. The fruits of the Spirit (see Galatians 5:22-23).
After a year-long separation, my parents divorced in 2006. Certain indicators emerged prior to that. I found myself in a perfect storm of trials. As you may have already read, I had a serious handicap of falsehood. The "way of lying" (Psalms 119:29) was slowly dying off in me and God was beginning to develop my heart and renew my mind to His truth.
But the devil doesn't play fair. He used this occasion to try and "sift me as wheat" (Luke 22:3) like he did Peter. But God, ever the opportunist, took these circumstances and worked them together for my good.
"And we know that all things work together for good to them that love God, to them who are the called according to His purpose." (Romans 8:28) But we don't truly get to know this fact unless we agree to go through those "all things" as it says.
One of the greatest lessons I've ever learned is to see Jesus as my center. He's the "anchor" of my soul (see Hebrews 6:19). He calms my worried mind (see Psalm 94:19) with not only a feeling—a presence of comfort (see Matthew 11:28-30)—but with a greater logic than my mind can assert or attain without Him. It's all about Him.
A person's confidence is an important and powerful thing. (I would venture so far as to say that it is the invisible currency that makes society go 'round. But that's a story for another time…) As Christians we need to be sure that our confidence is in God and not ourselves (see Philippians 3:3). God will rebuild you from the ground up if need be. It can be a long and trying process but it's worth every ounce of effort you put into it.
Peter found this out. In the Book of Acts, he is a transformed individual.
"In the fear of the Lord is strong confidence: and His children shall have a place of refuge." (Proverbs 14:26)