The Anahata Chakra
The fourth chakra, the chakra of the heart, is the place where resides our Spirit, our true Self, which is eternally pure and unaffected by anything, like a shining diamond hidden within us which witnesses all our actions. After Self Realization, our attention becomes for the first time connected to our Spirit and we gradually become aware of it. Our misidentifications with our ego or conditionings drop and we start becoming identified with our Spirit, which is our true nature.
On the physical level, this chakra looks after our heart and lungs - if affected it can cause asthma or various heart conditions.
It is from our heart that the compassion and love manifests, and also the heart chakra is the one that gives us the sense of responsibility and pure behaviour towards others. The heart chakra manifests in the center (at the level of the sternum bone) as complete security and confidence. All our worries, doubts and fears are destroyed when the heart chakra is fully enlightened by the Kundalini.