The word Ahad comes from the word Wahdah (unity). The word Ahad is the same as the word Wahid which means “One”. The word Ahad can function as a “name” and can also be a “property” for something. If it is positioned as an attribute, then it is only used for Allah SWT alone. In terms of language, the word Ahad, although it has the same root as Wahid, each has its own meaning and usage. The word Ahad is used for something abstract because this word does not include a series of numbers. If the word Wahid means one and is a number.
The oneness of Allah SWT as stated in Surah Al Ikhlas can be seen in four ways. First, the Oneness of Essence, which implies that one must believe that Allah does not consist of elements or parts. Because if the Almighty Essence consists of two or more elements then He needs that element or part. This is contrary to God’s nature which does not need anything.
Second, the Oneness of Attributes, which means that Allah has properties that are not the same in His substance and capacity compared to the nature of His creatures. Although in terms of language, the words used indicate the same nature. For example, the word Rahim is an attribute for Allah but is also used to designate mercy to creatures. But the substance and capacity of God’s mercy is different from the mercy of His creatures. Allah is One in His nature, so that nothing can match the substance and capacity of that attribute.
Third, Oneness in Action. This implies that everything that exists in this universe, both its working system and its causes and manifestations, are all acts of God alone. What He wills will happen and what He does not will will not happen. There is no power (to gain benefits), nor is there power (to resist harm) unless it comes from Allah. This does not mean that God acts arbitrarily or “works” without a system. The oneness of His actions is associated with the law or destiny and sunatullah that He has determined. These three onenesses are things to be known and believed in.
Fourth, Oneness Worship sincerely to Him. This fourth Oneness is the embodiment of the three previous meanings of Oneness. Worship is diverse. One of the most obvious variations is a certain practice, the method and measure determined by Allah through His Messenger. This is popularly known as mahdhah (pure) worship.