There is a center in the heart, which we call ‘Left Heart’. This is not the center of the heart. In a way it is the reflection of Shri Maha Deva (literally ‘Greatest God’) in the heart. The abode of Shiva is above our minds and thoughts.
To attain Shiva Tattva (the Shiva principle) we have to see how pure our heart is. We give place to many evil thoughts in our hearts, for example, jealousy. There is no use of becoming jealous: we should not feel jealous of any one. They might have harassed us or done harm to us, jealousy does no good to you. If your heart is pure then the mirror in which the reflection of Lord Shiva has to come will remain pure. But if you are full of jealousy then the mirror will not remain clean and as such the reflection of Lord Shiva will also not be perfect. Enmity and ill feelings for others are not to be fostered in the heart. That is why Christ has sad to forgive everyone. Forgiving is very important. Many saints, before and after Christ, have said the same thing, “Forgive everyone”. The moment you forgive your enemy, immediately Lord Shiva takes over. The power of Shri Mahadeva is the subtlest and it punishes the evil doer in a nice way. This is the work of Lord Shiva, its not your work.