Warning against hypocrisy
5) Narrated Mahmud bin Labid :Allah's Messenger said: The most dreadful thing which I fear about you is minor polytheism. The companions asked: What is the minor polytheism? He said: It is hypocrisy; and he added that on the Day of Judgment, when rewarding people for their deeds, Allah will say to the hypocrites: Go to those for the sake of whom you used to perform good deeds; and see whether you can get any reward from them.
(This Haditb is sound and mentioned in Musnad Ahmad).