(In their hearts is a disease), doubt, hypocrisy, conflict and darkness (so Allah increaseth their disease), increased their doubt, hypocrisy, conflict and darkness. (And a painful doom is theirs), they will have a painful torment in the Hereafter which shall extend to their hearts, (because they lie) in secret, the reference here being to the hypocrites: 'Abdullah ibn Ubayy, Jadd Ibn Qays and Mu'attib Ibn Qushayr.