Invoking brings the heart closer to the hereafter and keeps the world away from the heart, even though the world is around it. Invoking warns the heedless heart to abandon its pleasures and deceptions.
Let your invocation be the all-embracing Name, which is Allah, Allah, Allah, or if you so wish, Huwa, Huwa, Huwa; and do not violate this remembrance. Be careful lest your tongue pronounce it while other-than-He is in your heart. Let your heart be the one who utters, and your ear the one who is attentive to this invocation until the 'speaker' emanates from your Self (sirr). When you feel the emergence of the Speaker within you through the invocation, do not abandon the spiritual condition wherein you find yourself.
Know that the science of unveiling has no end to it, for it consists in the journey of the intellect in the stations of Majesty, Beauty, Sublimeness, Grandeur, and Holiness. . . . He to whom the mysteries of La ilaha illa'llah are revealed draws near to God, and his worship of God becomes sincere. He does not turn to anyone but to Him, nor does he have hope in or fear other than Him, nor does he see harm or benefit except as coming from Him. He abandons whosoever is not He and rids himself of inward and outward associationism (shirk).
Whosoever is determined to seek guidance and follow a path of right conduct must search for a shaykh from amongst those who have realization, one who follows a path methodically, who has abandoned his passions, and who has firmly established his feet in the service of his Lord.
Extinction is the beginning of the path: it is traveling to God Most High. Guidance comes afterwards. What I mean by guidance is the guidance of God, as described by the Friend of God, Abraham: "Lo! I am going unto my Lord Who will guide me.
The signs of the soundness of the servant's love for his Lord are three: absence of self-willing; pleasure in every event which takes place through divine decree; and seeing the perfection of the Beloved in everything and being content with Him in everything through submission to Him in all things.