There is much that goes in to being a peacemaker. To simplify it and to boil it down to its essence, it is doing what you must do to be at peace as long as it doesn't violate Scripture or your conscience. It is not going with your flesh, it is holding your tongue, it is not taking into account a wrong suffered, it is taking the blow (physical or otherwise), it is not being vindictive, it is having your vanity stepped on, it is having your feathers ruffled, it is suffering for righteousness sake. It is doing all of these without striking back or standing up for yourself or lashing out.
There are daily situations with family, friends, co-workers, vendors, other drivers, and a myriad of other scenarios where we must do the right thing and be the peacemaker. It will be up to us to bring peace, or to maintain peace, or simply to take the short end of the stick so that peace will reign. When we do that we are blessed. When we do that we bring glory to God. When we do that we are being like Christ who took the blows (physically and verbally) from the very ones whom He came to save.
So, let us not stand up for ourselves, but stand up for Him in keeping peace and making peace.
These verses in John, and the context of the verse in II Peter are dealing with moral cleanness and moral purity. A mark of the true Christian is that once they have been morally cleansed, they no longer desire to be morally filthy. Their new reality is not only do they not want to be morally filthy, but when they defile themselves with sin of even the least amount it bothers them, a feeling in the conscience much like the physical feeling of getting slimy mud on freshly washed hands.
Our reality is that we have been made clean in Christ (I Peter 3:21, Zechariah 3:3-5), washed from the inside out by the washing of the water by the word (Ephesians 5:2), and having our consciences cleansed by His blood (Hebrews 9:14). We are filthy no longer, and have no desire to return to the mire of our former life, but practice cleanliness (II Corinthians 7:1). However, when we defile ourselves with sin, we are quick to wash ourselves by the confession of that sin so that we can be clean again before our God (I John 1:9).
So, my friends, is this your reality? Have you been cleansed from the inside out? Is your desire to remain clean? Does it bother you to defile yourself with sin, and when you do sin, are you quick to confess it so that you can be cleansed from that sin?
One more note. If you truly confess your sins, He will always forgive you, and you will be made clean...no matter how filthy you made yourself before. Come to the Healer and Cleanser of your soul today. Ask Him to make you clean, and you will be clean indeed.