" The soul of man is the spark of God. Though this spark is limited on the earth, still God is all-powerful; and by teaching the prayer 'Thy kingdom come, Thy will be done on earth as it is in heaven', the Master has given a key to every soul who repeats this prayer; a key to open that door behind which is the secret of that almighty power and perfect wisdom which raises the soul above all limitations. "

― Hazrat Inayat Khan , The Way of Illumination (The Sufi Teachings of Hazrat Inayat Khan Book 1)