Every action of ours that we take initially takes place in our hearts before it then plays out physically for people to see. The state of our hearts matters a lot because it has a great way of influencing our actions. We should not let whatever that has the potential of corrupting our minds to find it's way too our hearts.
Here is what the Bible has to tell us in the book of Proverbs 2 vs 23 with concerning our hearts:
Proverbs 4:23 KJV
Keep thy heart with all diligence; For out of it are the issues of life.
We have to intentionally guard our hearts with all diligence. When we guard something it practically means that we treasure it. When our hearts become open to what is not supposed to be exposed to it stands a high chance of being corrupted. A pure heart would never have intentions of hurting or being harm to someone.
But a heart which has come under an influence which is negative is the type that would hurt people that are even the closest to him. But when we have the right spirit in us it leads to walk in love and purifies or hearts.