Not acting on knowledge causes harm to the student and is a proof against him

Shaykh Muhammad ibn Saalih al Uthaymeen stated:

Therefore it is a must for the student of knowledge to act upon (his) knowledge. So if he does not act, then knowledge becomes a harm upon him and a proof against him. And therefore the Prophet ‘alaihis salaatu wassalaam said:

The Qur-aan is a proof for you or against you.[1]

And know that if you act upon knowledge, you will be earning worship and an increase in your knowledge because Allaah says:

And as for those who accept guidance, He (Allaah) increases them in guidance and bestows upon their taqwaa.

SoorahMuhammad (47) aayah 17

So (as for) knowledge, then Allaah certainly increases people by it and He lowers others. So whoever seeks knowledge forAllaah, obeying His command and wishing to sincerely advise His servants –Allaah will raise him.

Allaah, the Most High, said:

Allaah raises in degree those of you who believe and those who have been granted knowledge.

Soorahal Mujaadilah (58) aayah 11

Therefore I urge you, my brothers, upon acting upon knowledge such that it becomes light for you and a means of increase by which you may be guided.

(Quoted in Wasaayaa wa tawjeehaat li tullaab il ‘ilm p142, translated by Nasser ibn Najam)