"O ye that believe! Fear God, and believe in His Apostle, and He will bestow on you a double portion of His Mercy: He will provide for you a Light by which ye shall walk (straight in your path), and He will forgive you (your past): for God is Oft-Forgiving, Most Merciful."
 

Source: Holy Qur'an (57:28) Yusufali's translation

"Purpose of the Light of Guidance: Let us study the verse (57:28) carefully: Is it not the same light of guidance which is permanent and everlasting and the purpose of which is that both the community and individuals have to walk on the straight path and advance in its light? Indeed, Islam is that straight path in whose stages of shariat, tariqat, haqqiqat and marifat, every travelling mu'min can progress to its ultimate limit."
 

Source: Rubies & Pearls, p.120

"Following the Prophets and True Imams: There is a great wisdom in this heading, because following the Prophets and True Imams is not an ordinary matter as their path (the straight path) and its stages are full of the pearls and diamonds of spirituality, luminosity, knowledge and recognition, and the duty of office of the True Guide cannot be fulfilled until he makes his followers reach the desired destination, i.e. annihilation or merging in God (marifat; monoreality). However, if the followers lose courage and lag behind, then they are responsible for their own failures."
 

Source: Rubies & Pearls, p.121