1 Peter 2:1-2

So put aside every trace of malice and all deceit and hypocrisy and envy and all slander and hateful speech; like a newborn baby (you should) long for the pure milk of the Word, so that by it you may be nurtured and grow in respect to salvation (its ultimate fulfillment).

Our salvation is the key to letting go of the past and all the emotional turmoil the unsaved mind used to focus on. We clean the slate and relearn how to think, react, and respond to circumstances. Where we used to hate, we walked away in love. When we used to criticize, we now speak encouragement.