Ibn al-Qayyim (may Allah have mercy on him) described the greatness of Allah in a most beautiful way:
He is controlling the affairs of all the kingdoms. He commands and prohibits, creates and gives provision, and gives death and gives life. He raises and lowers people’s status, alternates night and day, gives days (good and not so good) to men by turns, and causes nations to rise and fall, so that one nation vanishes and another emerges. His command and decree are carried out throughout the heavens and on earth, above it and below it, in the oceans and in the air. He has knowledge of all things and knows the number of all things. He hears all voices, and does not mistake one for another; He hears them all, in all the different languages and with all their varied requests and pleas. No voice distracts Him from hearing another, He does not confuse their requests, and He never tires of hearing the pleas of those in need. He sees all that is visible, even the walk of a black ant across a solid rock in the darkest night.
The unseen is visible to Him, and secrets are known to Him. Whosoever is in the heavens and on earth begs of Him (its needs from Him). Every day He has a matter to bring forth (such as giving honour to some, disgrace to some, life to some, death to some, etc.)! [The Quran 55:29 interpretation of the meaning]. He forgives sins, eases worries, relieves distress, helps the defeated person back on his feet, makes the poor rich, guides the one who is astray and confused, fulfils the needs of the desperate, feeds the hungry, clothes the naked, conceals faults, and calms fears. He raises the status of some and lowers the status of others. Even if all the inhabitants of heaven and earth, the first and the last of them, mankind and jinn alike, were to be as pious as the most pious among them, this would not increase His sovereignty in the slightest; if they all, the first and the last of them, mankind and jinn alike, were to be as rebellious as the most rebellious among them, this would not decrease His sovereignty in the slightest. If everything in heaven and on earth, the first and the last of them, mankind and jinn, living and dead, animate and inanimate, were to stand in one place and ask of Him, and He were to give them everything that they asked for, this would not decrease what He has by even an atom’s weight.
He is the First, before Whom there is nothing, and the Last, after Whom there is nothing. He is the Most deserving of being remembered, the Most deserving of being worshipped, the Most deserving of being thanked. He is the Most Compassionate of kings, the Most Generous of those who are asked. He is the King Who has no partner or associate, the One who has no rival, the Self-Sufficient Master, Who has no son, the Most High, and there is none like unto Him. Everything will perish save His face [Quran 28:88], and everything will vanish except His sovereignty. He will not be obeyed except by His permission, and He will not be disobeyed except with His knowledge. He is obeyed, so He shows His appreciation, and He is disobeyed, so he forgives. Every punishment on His part is justice, and every blessing from Him is a favour. He is the closest of witnesses and the nearest of protectors. He seizes people by their forelocks, records their deeds and decrees the appointed time for all things. Hearts conceal nothing from Him, for secrets are known to Him. His gift is a word and His punishment is a word: Verily, His Command, when He intends a thing, is only that He says to it, Be! and it is. [Quran, 36:82].
Source: al-Waabil al-Sayyib, p. 125
This is Allah, who revealed the Glorious Quran for the guidance of mankind.