The Punishment for Not Acting upon One's Knowledge

On the authority of Usamah ibn Zayd (radhyAllahu ‘anhu) that he heard the Messenger of Allah (sallAllahu ‘alaihi wasallam) sitting, "A man will be brought on the Day of Resurrection and thrown into the Fire. His intestines will be hanging out, spilling onto the ground, and he will go around like a donkey goes around a millstone. The inhabitants of the Fire will gather around him and say: "O so and so! What is your affair? Didn't you used to order us to do good deeds and forbid us from doing bad deeds?" He will reply, "Yes I used to order you to do good deeds, but I did not do them myself, and I used to forbid you from doing bad deeds, yet I used to do them myself". (Reported by al Bukhari, Engl. trans. vol.4, p.315, no. 489; Muslim and others).

The Messenger (sallAllahu ‘alaihi wasallam) also said in a hadith, "During the night of my ascension, I passed by a group of people. Their lips were being severed with scissors of fire. I said, "O Jibreel (alaihis salam)! Who are these people?" He said, "They are the preachers from your Ummah that would say other than what they would do". (Reported by Ahmad in his Musnad, 3/120, 231, and 239; Ibn Hibban and others, Sahih at-Targheeb, no.120).

On the authority of 'Umar ibn al Khattab (radhyAllahu ‘anhu) who said that the Messenger of Allah (sallAllahu ‘alaihi wasallam) said, "Islam will dominate so that traders frequent the seas and horses enter into the path of Allah. Then there will appear a people who will recite the Qur'an saying, "Who amongst us had memorised the most Qur'an? Who is the most knowledgeable of us? Which of us has the most understanding?" Then he (sallAllahu ‘alaihi wasallam) asked his companions, "Is there any good in them?" They replied, "Allah and His Messenger (saw) know best". He (sallAllahu ‘alaihi wasallam) said, "They are from you and from this ummah and they are from the fuel of the fire". (Reported by at-Tabarani, in al-Awsat and al-Bazzar, Sahih at-Targheeb wa at-Tarheeb, no.131).

Also in the hadith, "The Qur'an is either a proof for you or against you". (Reported by Muslim, Engl. trans. vol.1, p.148, no.432; and others).

Trials Take Place When Knowledge is Sought for Other Than Actions:

On the authority of 'Ali (radhyAllahu ‘anhu) that he made mention of trials occuring at the end of time. 'Umar (radhyAllahu ‘anhu) asked him, "When will that be, O 'Ali?" He said, "When understanding of the religion is sought for other purposes, and knowledge is acquired for other than acting upon, and wordly gain is sought with the actions of the Hereafter".

('Abdar Razzaq in his Mussanaf as a statement of 'Ali. It is also in Sahih at-Targhib at-Tarhib, no.106)