On the authority of 'Abdullaah, who related that he heard the Messenger of the Merciful (sal-Allaahu `alayhe wa sallam) say:
((Whoever makes the Hereafter his sole concern, then the Almighty will be sufficient for him concerning his affairs and needs in the world, and whoever's concerns are divided amongst the affairs of the world, then the Almighty would have no care in which path he is destroyed)).
Reported by Ibn Maajah and others. Authenticated by Shaykh al-Albaanee in al-Mishkaat.