The phrase ABDU HU (HU’s servant) in the Kalima-i Shahadah (the Word of Witness), clearly indicates that servitude is necessarily to the Absolute Essence, that is, to HU.
As for the meaning of servitude… All output by an individual, based on his creation program and natural disposition, is termed servitude. As the 56th verse of chapter Adh-Dhariyat says:
“I have created the jinn and men only so that they may serve Me (by means of manifesting the qualities of My Names).”
As such, it is not possible for the creation of Allah to transgress the purpose of their existence. This verse indicates a clear verdict and its result. It is also pertinent to remember the verse:
“There is no animate being that He does not hold (program with the Name Fatir) by its forehead (brain)(i.e. subjugate to His command)...” (Quran 11:56)
In point of fact, the verse “it is You we serve” in the opening chapter al-Fatiha, exposes the meaning ‘we perform our duty by executing the necessary functions of our creational program and the purpose for which you have created us’.
“Say: ‘Everyone acts according to his own creation program (natural disposition; fitrah)’...” (Quran 17:84)
Servitude is the output of activity by individual manifestations, based on the creation program given to them by Al-FATIR. That is, when individuals live according to their natural disposition, they are serving the purpose of their creation.
Oblivious of submission or rebellion, all activities of all individuals can be thought of as servitude. Submission and rebellion are different types of servitude.
“The seven heavens (all creation pertaining to the seven states of consciousness), the earth (the body) and everything within them exalts Him (tasbih; fulfill their functions by constantly manifesting in different ways to express His Names)! There is nothing that does not exalt (tasbih) Him with hamd (evaluation of the corporeal worlds created with His Names, as He wills)! But you do not perceive their functions!” (Quran 17:44)
Servitude in the form of taat is the pursuit of an individual trying to know his essence and origin.
Servitude in the form of rebelliousness, on the other hand, is the collection of activities that prevent and deprive the individual from the treasures within his essence, which leads to remorse.
Therefore, while servitude refers to a lifestyle befitting one’s creational purpose, worship is the deification of a supposed god by honoring him and expecting him to grant your wishes in return.
Thus, it may be concluded that, God is worshipped, while Allah is served.
How then, should servitude to Allah be performed?
In order to answer this question one must first discern the AHAD quality of Allah. For if the AHAD quality is comprehended well, one can see (with foresight) that there is no duality in existence. The concept that there is Allah, and there is also the universe (outside of Allah) is obsolete.
In other words, the common approach that beyond and other than this cosmos there is a God is completely false.
Allah disclosed by Muhammad (saw) is not a god!
Allah disclosed by Muhammad (saw) is AHAD (ONE).
Allah disclosed by Muhammad (saw) is the possessor of infinite meanings, which He constantly observes!
The realm of observation is the realm of names.
 The Word of Witness is the testifying of the Word of Unity. It literally means: “I bear witness that there is no god, there is only Allah, and I bear witness that Muhammad is HU’s (Allah’s) Rasul and Servant.”