Do not covet anything avariciously; for if you ignore it, it will come to you anyway, if it is destined to be yours. Then you would find ease in your heart with Allah, praise for leaving it; but you will be blamed for your haste in seeking it, for not trusting Him, and for not being content with the decree. Allah created this world the same as a shadow: when you chase it, it tires you out and you can never catch up with it. If you leave it alone, it follows you inexorably, and gives you no cause for fatigue.
The Holy Prophet said, 'A covetous man is bereft; yet in spite of his deprivation, he is blamed wherever he is.' For how could he be other than bereft when he flees from the covenant of Allah, and opposes His words:
اللَّهُ الَّذِي خَلَقَكُمْ ثُمَّ رَزَقَكُمْ ثُمَّ يُمِيتُكُمْ ثُمَّ يُحْيِيكُمْ
The covetous person is in the midst of seven difficult evils: thinking, which harms his body but brings it no help; anxiety, which has no end; weariness, from which he will find rest only in death, although he has the greatest weariness when at rest; fear, which only makes him fall into what he fears; sorrow, which makes his livelihood disturbed without any benefit to him; reckoning, which will not save him from the punishment of Allah unless He pardons him, and punishment, from which there is neither flight nor escape.
The one who trusts in Allah spends morning and evening in His protection and well-being. Allah has hastened for him what suffices him, and prepared for him things which only Allah knows. Avarice is what flows out from Allah's anger. When the slave is not bereft of certainty, he is not covetous. Certainty is the earth of Islam and the heaven of iman.