The Prophet ﷺ is reported to have stated in a hadith:
سَلوا اللهَ عِلمًا نافعًا وتعَوَّذوا باللهِ مِن علمٍ لا ينفعُ
“Ask Allah for beneficial knowledge and seek refuge in Him from knowledge that does not benefit.”
[Saheeh Ibn Majah 3114]
Ibn Rajab al-Hanbali said:
“Beneficial knowledge is that which directly impacts the heart, enhancing within it the recognition and magnification of Allah the Exalted, along with awe, reverence, veneration, and love for Him. When these matters settle within the heart, it becomes humble, and as a result, all limbs humbly submit in accordance with its humility.
In Sahih Muslim, it is narrated from the Prophet ﷺ that he used to say: ‘I seek refuge in You from knowledge that does not benefit and from a heart that does not humble.’
This indicates that knowledge that does not induce humility in the heart is knowledge that is not beneficial.”
Source: كتاب ورثة الأنبياء شرح حديث أبي الدرداء
So those who embark on this journey, must ascertain that the knowledge they are spending so much time collecting is actually having an impact in their relationship with Allah and their actions, otherwise, there is something seriously wrong either in the type of knowledge they are gathering or their intentions.
Beneficial knowledge is that which purifies inner virtues, flows into outward actions, rectifies both the apparent and the hidden aspects. Beneficial knowledge is knowledge of the Sharia, which informs the accountable individual of what is obligatory in terms of their religious matters, worship, transactions, ethics, and conduct.
One of the signs of Allah’s desire for goodness for His servant is granting them success in seeking knowledge and understanding. The Prophet ﷺ said:
مَن يُرِدِ اللهُ به خيرًا يُفقِّهْه في الدِّينِ
“Whomever Allah intends good for, He makes them understand the religion.”
[Bukhari and Muslim]
Also among beneficial knowledge are worldly sciences that hold benefit and advantage for Muslims. When a Muslim learns them, intending them sincerely for the sake of Allah, and uses them for the benefit of Muslims, he/she benefits from them in both this world and the Hereafter.
Then the Prophet ﷺ said, “And seek refuge in Allah from knowledge that does not benefit.” Meaning, invoke Him and ask Him to protect you from being afflicted with knowledge that is not useful, which is knowledge not acted upon, not beneficial, and does not refine one’s morals, speech, or actions. It becomes a proof against its possessor and includes what is not permissible to learn.