Allah (ta'ala) says in the Quran:

O you who believe! Fear Allâh and keep your duty to Him. And let every person look to what he has sent forth for tomorrow, and fear Allâh. Verily, Allâh is All-Aware of what you do.

And be not like those who forgot Allâh (i.e. became disobedient to Allâh) and He caused them to forget their ownselves, (let them to forget to do righteous deeds). Those are the Fâsiqûn (rebellious, defiantly disobedient to Allâh).

(Al-Hashr 59:18-19)

Narrated Ibn 'Abbas (radi Allahu 'anhu): Once i was behind the Prophet (sul Allahu 'alayhi wassalaam) and he said: "O boy, i will teach you a few words :

(a) Be loyal and obedient to Allah [worship Him (Alone)], remember Him always, obey His Orders. He will save you from every evil and will take care of you in all the spheres of life.

(b) Be loyal and obedient to Allah, you will find Him near (infront of you), i.e. He will respond to your reqests.

(c) If you ask, ask Allah.

(d) If you seek help, seek help from Allah.

(e) Know that if all the people get together in order to benefit you with something, they will not be able to benefit you in anything except what Allah has decreed for you. And if they all get together in order to harm you with something, they will not be able to harm you in anything except what Allah has decreed for you.

The pens have stopped writings [Divine (Allah's) Preordainments]. And (the ink over) the papers (Bood of Decrees) have dried." [Sahih At-Tirmidhi]

Shaikh ul-Islam Ibn Al-Qayyim (rahimahullah) in Al-Jawab al-Kafi said:

And among its effects is that the disobedient (sinner) is constantly in the shackles of his Shaytaan and the prison of his shahwa (desires) and the chains/fetters of his hawaa (whims). So he is a captive, one who is imprisoned and who is tied up.

There is no captive in a worse state than the one who is captivated by his worst enemy and there is no prison which is tighter than the prison of hawa and there is no bond/fetter more strong than the bond of desire.

How, then, will a heart which is captivated, imprisoned and fettered travel unto Allaah and the Home of the Hereafter. How will a person take a single step forward when the heart is bound and harmful things approach it from every direction. The harmful things approach it to the extent that it is tied up [i.e. imprisoned by its desires and whims..].

The example of the heart is like the example of a bird. Every time is ascends it becomes distant from the harmful things and every time it descends the harmful things hurt it. In a hadeeth there occurs that Shaytaan is like a wolf to people. Just as when a sheep has no protector and is in between many wolves, they are quick in causing damage and injury; likewise the servant who does not have guardianship from Allaah, then his wolf [i.e. his desires, whims etc.] is to him a predatory animal.

[Thus] there is no escape for the servant from having protection from Allaah. Taqwaa is a safeguarding for him and a strong shield between himself and the punishment of this world and the Hereafter.

Every time the sheep is close to its shepherd it is more safe from the wolf and every time it becomes distant from its shepherd it is closer to destruction. So its sanctuary is when it is close to its shepherd because the wolf takes the lonely one from the flock and this is the one which is the furthest one of the flock from the shepherd. The basis of all of this is is that every time the heart is distant from Allaah the harmful things are quick in approaching it and every time it is close to Allaah the harmful things become distant from it.

The Messenger of Allah (Sul Allahu 'alayhi wassalaam) said: "Shall I not tell you the most in goodness of your deeds, the nicest to Your Owner, the highest in your ranks, better for you than spending gold and silver, and better for you than meeting your enemy whereupon you strike their necks and they strike your necks?" They said "Yes O' Messenger of Allah." He said: "Rememberance of Allah."