It is reported that ‘Abdullâh b. ‘Abbâs – Allâh be pleased with him – said, “Love for Allâh and hate for Allâh, make your enmity because of Allâh and your allegiance because of Allâh; for indeed, the love and support of Allâh is not achieved save through this. And a man will never taste true faith (îmân) – though he may pray and fast much – except when he is like that. Today, the people’s brotherhood is based upon worldly considerations (dunyâ), but this will not do anything for them on the Day of Resurrection.”
Ibn Al-Mubârak, Al-Zuhd wa Al-Raqâ`iq article 353.