Allaah is Greater
Allaah – the Most High – says:
“That He will call you to account for what your hearts have earned.” [Soorah al-Baqarah 2:225].
“The day when neither wealth nor children will be of any avail, except he who comes to Allaah with a dean and pure heart.” [Soorah ash-Shu’araa 79:88-89].
The Prophet sallallaahu ‘alayhi wa sallam said:
“Indeed, there is a piece of flesh in the body; if it is sound then all the body is sound. However, if it is diseased, then all the body is diseased Truly that is the heart.” 
Al-Haafidh Ibn Rajab (d.795H) – rahimahullaah -said:
“So know that the world – and whatever is above it and below it in the water- will not be corrected except when the actions of its people are all for Allaah. The actions of the body follow on from the actions and intentions of the heart. So when the actions and intentions of the heart are purely for Allaah alone, then it is corrected, and likewise the actions of the body will also be correct. However, if the actions and intentions of the heart are for other than Allaah, then it is corrupted, and likewise the actions of the body will be corrupted in proportion to how much the heart is corrupted.” 
And he said: “Hearts will not be corrected until the ma’rifah (knowledge and realisation) of Allaah – being in awe of His greatness, loving Him, fearing Him, hoping in Him, relying and trusting in Him – is not firmly implanted in them. This is the reality of Tawheed and the meaning of the saying: Laa ilaaha illallaah (that none has the right to be worshipped except Allaah). Thus, hearts will not be corrected until Allaah is made the ilaah (deity) to be known, to be loved, feared and hoped in, and that He – along with this – becomes the only ilaah (deity) worthy of this, without associating any partner to Him in this.” 
Indeed, we may begin to appreciate the greatness of Allaah – the Most High’s – and being in awe of Him, by considering some narrations regarding what He – the Most High – has created.
The Prophet sallallaahu ‘alayhi wa sallam said:
“Indeed I see what you do not see and hear what you do not hear. Heaven has groaned, and it has a right to do so. By Him in Whose Hand is my soul! There is not in the heaven a space equivalent to four fingers, except than an angel has prostrated his forehead to Allaah in it. By Allaah! If you knew what I know, you would laugh little and weep a lot, and you would not take delight in women in their beds, but rather would go to the wilderness and implore Allaah for help.” 
He sallallaahu ‘alayhi wa sallam said:
“The seven Heavens compared to the Kursee (the Chair) is like a ring which is thrown into a desert. And such is the magnitude of the ‘Arsh (the Throne of Allaah) compared with the Kursee.” 
He sallallaahu ‘alayhi wa sallam also said:
“I have been given permission to relate to you about the Angels of Allaah – the Most High – that carry the ‘Arsh (Throne). Between one of the Angel’s ear and shoulder is a distance of seven hundred year journey.” 
And he sallallaahu ‘alayhi wa sallam also said:
“Al-Baytul-Mamoor is in the seventh heaven [directly above the Ka ‘bah]. Each day seventy thousand angels enter it, and they will not return until the Day of Resurrection.” 
So: “the need of the servants for this (type of) knowledge is greater then every other need; end it is the most necessary of all things for them, since there is no life for the hearts, nor any delight, nor any tranquility, except through knowing their Lord, the only One Who deserves to be worshipped, their Creator – with His Names, His Attributes and His Actions, and that He – along with all that – is more beloved to the person than anything else. So man’s striving is with regards to everything that will draw him nearer to Allaah, to the exclusion of the creation … So the people who know Allaah the best, are the ones who best follow the way to Him; and know best whet lies at the end of the way.” 
1.Related by al-Bukhaaree (1/126) and Muslim (no.1599) from an-Nu’maan ibn Basheer radiallaahu ‘anhumaa.
2. Jaami’ al-‘Uloom wal-Hikam (p120).
3. Jaami’ al-‘Uloom wal-Hikam (p.120).
4. Hasan: Related by Ibn Maajah (no.4190) and at-Tirmidhee (2/51),who authenticated it, from Abu Dharr radiallaahu ‘anhu.
5. Saheeh: Related by Ibn Abee Shaybah in Kitaabul-‘Arsh (1/114) and al-Bayhaqee in as-Asmaa was-Sifaat (p 290), from Abu Dharr radiallaahu ‘anhu. The hadeeth is authentic due to its various routes of transmission – as Shaykh al-Albaanee has explained in as-Saheehah (no.109).
6. Saheeh: Related by Abu Daawood (no.4727) and al-Bayhaqee in as-Asmaa was-Sifaat, (no.398), from Jaabir radiallaahu ‘anhu. It was authenticated by Imaam adh-Dhahobee in al-‘Uluww (p.58).
7. Saheeh: Related by Ahmad (3/153), from Anas radiallaahu ‘anhu. And the addition is related by Ibn Jareer at-Tabaree in his Tafseer (11/27). The hadeeth was authenticated by al-Albaanee in as-Saheehah (no.477).
8. Sharhul-‘Aqeedatit-Taahawiyyah (p.27) of Imaam Ibn Abil-‘lzz.