A bulging portfolio of spiritual experiences matters little if it does not have the power to sustain us through the inevitable moments of grief, loss, and change. Knowledge and achievements matter little if we do not yet know how to touch the heart of another and be touched. Wisdom is alive only as long as it is lived, understanding is liberating only as long as it is applied.
Concentration is not thinking of one thing. On the contrary, it is excluding all thoughts, since all thoughts obstruct the sense of one's true being. All efforts are to be directed simply to removing the veil of ignorance. Concentrating the mind solely on the Self will lead to happiness or bliss. Drawing in the thoughts, restraining them and preventing them from straying outwards is called detachment (vairagya). Fixing them in the Self is spiritual practice (sadhana). Concentrating on the heart is the same as concentrating on the Self. Heart is another name for Self.
A man does not have to go and find where his eyes are in order to see. The heart is there, always open to you, if you care to enter it, always supporting your movements, although you may be unaware of it. It is perhaps more correct to say that the Self is the Heart. Really the Self is the centre and is everywhere aware of itself as the Heart or Self-awareness.
Place your burden at the feet of the Lord of the universe who is ever victorious and accomplishes everything. Remain all the time steadfast in the heart, in the Transcendental Absolute. God knows the past, present and future. He will determine the future for you and accomplish the work. What is to be done will be done at the proper time. Don't worry. Abide in the heart and surrender your acts to the Divine.
When you truly feel this equal love for all, when your heart has expanded so much that it embraces the whole of creation, you will certainly not feel like giving up this or that. You will simply drop off from secular life as a ripe fruit drops from the branch of a tree. You will feel that the whole world is your home.