In Genesis 4 we read the story of Cain and Abel. While the story is very short I believe it took much longer for Cain to work out his plan against Abel. Most people don't go from one rejection and make the leap to murder. I think it took a while. I think Cain had allowed his rejection to fester. I think he nursed the hurt he felt and began to focus his hatred towards what he perceived to be the root cause of his self-loathing, his brother Abel.
Light and darkness cannot live together. They cannot co-exist for long without something exploding, without a confrontation. Abel had done what was right. He lived right and this made Cain's life look all wrong.
Those who go on a rampage don't usually wake up one morning and decide to murder people. It is usually a lifetime of rejection that has built up inside of them. They have allowed bitterness to take root in their lives and they find someone to blame for their rejection and short comings. They buy guns and knives, they write journals or keep logs of all the wrongs committed against them, they carefully rehearse the scenarios in their heads. Their whole life has now become focused on revenge, on a hurt that happened in the past. They have lost all connection to reality. They plot and wait for the right moment to carry out their evil plans.
With Cain it led to murder. We may not take it so far but far too many of us carry some sort of hurt that we have not dealt with. We've allowed it to take root in our lives. Even the thought of that person or that event brings us pain.
We are told in the scriptures to not allow the root of bitterness to take a hold of us.
Let us instead come boldly before the throne room of grace and find help for overcoming those past hurts. It's time to let them go before they bear fruit.