al-Wakīl is used in four senses:
1. al-Wakīl is used in the sense of protector (one who protects), as in the following verses:
...Or who will dispute with Allah for them on the Day of Resurrection, or who will be a wakīl {that is, who will protect them, who will prevent the dangers that will befall them} for them? (al-Nisāʾ 4:109)
Indeed, My servants {that is, My servants who are muwaḥḥidūn (those who affirm tawhid, the oneness of God)!}, you have no authority over them; and sufficient is your Lord as a wakīl {that is, as a protector who prevents dangers from befalling His muwaḥḥid servants}. (al-Isrāʾ 17:65)
2. Wakīl is used in the sense of rabb (Lord), as in the following verses:
So take Him as a wakīl {that is, as Lord}! (al-Muzzammil 73:9)
...Do not take anyone besides Me as a wakīl {that is, as Lord}. (al-Isrāʾ 17:2)
...So worship Him and He is wakīl over all things {that is, He is the Lord of all things}. (al-Anʿām 6:102)
A similar example is also found in Sūrat al-Zumar.
3. The word wakīl is used in the sense of a tyrannical ruler, as in the following verses:
We have not made you a wakīl {that is, a tyrannical ruler} over them. (al-Anʿām 6:107)
It is the truth, but your people have denied it. Say: "I am not a wakīl {that is, a tyrannical ruler} over you." (al-Anʿām 6:66)
Will you then be a wakīl {that is, a tyrannical ruler} over him? (al-Furqān 25:43)
In all the expressions in the Qur'an where it says, "You are not a wakīl over them," the word carries this meaning.
4. Wakīl is used in the sense of witness (shāhid), as in the following verses:
To Allah belongs whatever is in the heavens and whatever is on the earth {that is, they are His servants and belong to His dominion}; and sufficient is Allah as a wakīl {that is, as a witness/testifier that they are His servants}. (al-Nisāʾ 4:132)
He is exalted above having a child. To Him belongs whatever is in the heavens and whatever is on the earth {that is, they are His servants and belong to His dominion}; and sufficient is Allah as a wakīl {that is, as a witness/testifier that those in the heavens and earth are His servants}. (al-Nisāʾ 4:171)
You are only a warner, and Allah is wakīl over all things {that is, He is a witness/testifier that you are His Messenger}. (Hūd 11:12)
Allah is wakīl over what we say {that is, He is a witness/testifier}. (Yūsuf 12:66)
{Mūsā said:} "Allah is wakīl over what we say" {that is, He is a witness/testifier}. (al-Qaṣaṣ 28:28)