Nice story from Abdu'l-Baha:
“There was once a disciple of Muhammad who asked of another disciple, ‘What shall I do to please God?’ And the other disciple replied: ‘Do not kill. Do not steal. Do not covet,’ etc., etc., etc. A great many ‘do not's’” then “He asked still another, ‘What shall I do to become nearer to God?’ And this one said: ‘You must supplicate and pray. You must be generous. You must be courageous,’ etc., etc., etc. Then the disciple went to ‘Ali. ‘What do you say I should do in order to please God and to become nearer to Him?’ ‘One thing only: be truthful.’” Abdul-Baha said “if you are truthful, you cannot commit murder. You would have to confess it! Neither can you steal. You would have to confess it. So, if one is truthful, he possesses all the virtues.