"Do not be over come with evil, but overcome evil with (or by doing) good." Romans 12:21
Whenever a challenging situation happens, or or if someone offends us, it is so easy for anger or displeasure to poor out of us. But this is not helpful, nor is it the right thing to do. We don't like to call that which is in us evil, but let's do. Let's call a spade a spade. Let's not mix words. As long as we deny the evil that tries to control us we give it control over us. Let us call evil for what it is, and then we can deal with it. To overcome (the) evil (that is in us) we must be quick to do good, to be helpful, to say a kind work, to do what is right. For instance, whenever someone does something that displeases us, rather than being angry, cruel... it is better to do or say something that is kind and helpful
We replace our negative thoughts and emotions with kindness because it, changes our emotions, builds rather than tears down relationships, makes us into better kinder people. We become what we say or do. When we do mean things, we become mean people. Conversely, when we do kind deeds, we become kinder people.