In The Name of Allaah, The Most Merciful, The Bestower of Mercy
If a person begins the day and reaches the evening, whilst his [foremost] concern is [to obey or seek the pleasure of Allaah], Allaah [Glorified be He and free is He from all imperfections] will fulfil all his needs, take care of everything that worries him, [free his heart from other things and busy it with] love of Allaah, [preoccupy] his tongue with remembrance of Allaah and His limbs with acts of obedience to Allaah.
And if he begins the day and reaches the evening whilst his [foremost] concern is the worldly life, Allaah will make him carry the displeasure of his worries and griefs, leave him to himself, preoccupy his heart with love of the creation instead of love of Allaah, [preoccupy] his tongue with remembrance of the people instead of remembrance of Allaah, [preoccupy] his limbs with obedience to [people] by serving them and being busy in their service, instead of being obedient to Allaah; so he toils in their service just like the bellows that blows and squeezes for the benefit of others. Everyone who turns away from servitude to Allaah, obedience to Allaah and love of Allaah, he will be afflicted with servitude to a created thing, love of it and serving it. Allaah [The Exalted] said: [ وَمَن يَعْشُ عَن ذِكْرِ الرَّحْمَٰنِ نُقَيِّضْ لَهُ شَيْطَانًا فَهُوَ لَهُ قَرِينٌ– And whosoever turns away [blinds himself] from the remembrance of the Most Beneficent [Allaah], We appoint for him Shaitan [Satan – devil] to be a Qareen [an intimate companion] to him. [Surah Az-Zukhruf. Aayah 36]
Source: An Excerpt from ‘Al-Fawaa’id’ page 134-135. Slightly paraphrased