Your own Self-realization is the greatest service you can render the world. - Ramana Maharshi

There is no duality. Your present knowledge is due to the ego and is only relative. Relative knowledge requires a subject and an object, whereas the awareness of the Self is absolute and requires no object.

If other thoughts rise, one should, without attempting to complete them, enquire, 'To whom did they arise?', it will be known 'To me'. If one then enquires 'Who am I?', the mind (power of attention) will turn back to its source. By repeatedly practising thus, the power of the mind to abide in its source increases.

Know Thyself. All else will be known to thee of its own accord. Discriminate between the undying, unchanging, all-pervading, infinite Atma and the ever-changing, phenomenal and perishable universe and body. Enquire, "Who am I?" Make the mind calm. Free yourself from all thoughts other than the simple thought of the Self or Atma. Dive deep into the chambers of your heart. Find out the real, infinite "I". Rest there peacefully for ever and become identical with the Supreme Self.