1. Jabbaar is something so lofty which one cannot reach. Allaah Jalla Jalaalahoo is that Being Who is far above one’s thoughts and understanding. All intelligentsia and ulamaa, are deficient in understanding His Reality.

2. Jabbaar refers to the person who mends something. It is derived from the word جبر الكسر (He mended the broken bone) and جبر الفقير (He fulfilled the needs of the poor/ mended his condition).
Allaah Jalla Jalaalahoo is that Being Who Corrects all matters and makes all difficulties easy. He Chooses for them that in which there is goodness for them.”

3. The Arabs say:

جبره على كذا إذا كرهه
“Jabr refers to when one forces another, to do according to his wish.”  

Al-Jabbaar is that Being Who Subjugates His Creation to a Command or Prohibition, according to His Intention.
Some ulama have stated:

لا يجري في سلطانه بخلاف مراده
“Nothing occurs in His Sovereignty, contrary to His Desire.” (Mirqaat)

Take a look; without any aspirations, many matters occur which are contrary to one’s nature. Great kings are the possessors of huge armies and many servants. In spite of this, there are many things that they wish to do, but cannot. Some matters are such, which they do not want to occur, but they do take place.

A. Firaun made a great effort to ensure that Sayyiduna Musa Alayhis Salaam should not come into the world. However, Al-Jabbaar Nurtured Sayyiduna Musa  Alayhis Salaam in Firaun’s own house.
B. Namrud made effort to make sure that Sayyiduna Ibrahim Alayhis Salaam’s call should not spread, but Al-Jabbaar made his call of Tawheed spread.
C. The polytheists of Makkah Mukarramah made great efforts to stop the da’wat (invitation) of Sayyiduna Rasulullah SalAllaahu Alaihi Wasallam, but they were unsuccessful. Al-Jabbaar Made their own youth rise against them. Thus Al-Jabbaar is that Being Who, if He Wishes for something to occur in His Kingdom, it definitely does; and none can be an obstacle to His Will. If He does not wish for something to occur, it can never take place.

In a hadith-qudsi, Allaah Jalla Jalaalahoo states :

 

عبدي تريدُ واريدُ ولا يكون الا ما اريدُ فان رضيتَ بما اريدُ كفيتُك ما تُريدُ وان لم ترض بما اريدُ أتعَبْتُكَ فيما تُريدُ ثم لا يكون الا ما أريدُ
“My slave, you decide something, and I Decide, and only what I Decide will occur. Thus if you are pleased with that which I Decide, then I will be Sufficient for you in that which you had decided, and if you are not pleased with that which I Decide, then I will Tire you in going after that which you had desired, and then too, only that which I had Decided will occur.” (Teebi)

Imaam Raazi Rahimahullaah said,
“Complete greatness is only and solely for Allaah Jalla Jalaalahoo. Allaah Jalla Jalaalahoo has praised Himself with this Name of Al-Jabbaar. However, when used in relation to the creation, this name is disliked. What is the difference? The difference is that Allaah Jalla Jalaalahoo Overpowers all tyrants by His Greatness and He Surpasses them by His Grandeur. No judgment of any leader is adopted over Him that it is compulsory to Him to follow, nor does the command of any commander turn towards Him in such a manner, that its obedience is binding on Him. He is the One Who Gives Commands, not one who is commanded. He Overpowers and is not overpowered." 

Allaah Jalla Jalaalahoo States, ‘He will not be questioned regarding what He Does, and they (creation) will be questioned.’ (Ambiyaa)

On the other hand, the creation is characterized with the qualities of weakness. They are subjugated. A small flea causes them harm, and even silkworms bite them. A bee causes them perplexity. They are a prisoner of their hunger, and desirous to satiate it. 
How can those who possess such qualities ever be characterized by greatness and grandeur?”