The words of remembrance of Allah clean our hearts, purify our souls and enable us to overpower Shaytan. Without strengthening our hearts through the remembrance of Allah, we cannot gain victory over Shaytan. He will constantly try to control our thoughts and, and even at the most important times, he will make us forget about Allah (SWT). Now, the third of those is the word Allahu Akbar. Allahu Akbar obviously means that Allah (AWJ) is the greatest, so the person that says Allahu Akbar says that everything is small in front of Allah (SWT). The whole world is small compared to him, and it actually is. One hadith says that this whole first sky between the second sky and third sky is a distance of maybe 500 years, and the first sky includes everything that we know about the universe. Above that is the second sky, and the first sky compared to the second sky is so small that it is almost like a person who takes a ring and tosses it into the middle of a field. Trying to look for that ring is very difficult. That is how small the first sky is compared to the second sky. Imagine how big the second sky is. However, the second sky compared to the third sky is just as small, and likewise, the fourth compared to the fifth is just as small, the fifth to the sixth, the sixth to the seventh. Above the seventh sky is a body of water. This body of water is so vast and big that all seven heavens in front of it are like seven rings tossed into the middle of a field. Above that is the Kursi, and above that is the Arsh (throne) of Allah.