The Holy Prophet صَلَّى اللّٰهِ عَلَيْهِ وَاٰلِهٖ وَسَلَّم said: آفَةُ الْعِلْمِ النِّسْيَانُ، وَاِضَاعَتُهُ اَنْ تُحَدِّثَ بِهِ غَيْرَ اَهْلِهٖ i.e. The bane of knowledge is to forget it. And telling an ineligible person a point of knowledge is wasting knowledge. (Musannaf Ibn-e-Abi Shaybah, vol. 13, pp. 344, Hadees 26663)
Explanation: In this blessed Hadees, two points have been mentioned regarding knowledge: What is the bane of knowledge? How is knowledge wasted?
Hakeem-ul-Ummah Mufti Ahmad Yar Khan Na’eemi رَحْمَةُ اللّٰهِ عَلَيْه said: As wealth and health are ruined due to some calamities, knowledge is also ruined due to forgetfulness. (Mirat-ul-Manajih, vol. 1, pp. 224)
Refrain from forgetfulness- the bane of knowledge
The bane of knowledge i.e. forgetfulness is not a minor issue. In fact, it is a huge one. How to refrain from this calamity. Regarding it, Mufti Ahmad Yar Khan رَحْمَةُ اللّٰهِ عَلَيْه stated: An Islamic scholar should engage himself in scholarly activities. He shouldn’t give up reading [Islamic] books and should keep from the habits and things which weaken memory. (Ibid)
Sayyiduna ‘Allamah Ali Qaari رَحْمَةُ اللّٰهِ عَلَيْه has narrated that one should refrain from the causes of forgetfulness. For example, he should neither give up revising knowledge nor should he get involved in the activities which cause his heart to be entrapped by the charms of the world, wasting his intellect. (Mirqat-ul-Mafateeh, vol. 1, pp. 523, Taht-al-Hadees 265)
Causes of forgetfulness
A big cause of forgetfulness - the bane of knowledge, is sin which weakens memory. Therefore, Sayyiduna Imam Shafi’i رَحْمَةُ اللّٰهِ عَلَيْه has stated:
شَكَوْتُ إِلىٰ وَكِيْعٍ سُوْ ءَ حِفْظِی
فَأَوْصَانِيْ إِلىٰ تَرْكِ المَعَاصِيْ
فَاِنَّ العِلْمَ فَضْلٌ مِنْ الٰہٍ
وَفَضْلُ اللّٰهِ لَا يُعْطیٰ لِعَاصِی
Translation: I made a complaint about my weak memory to my teacher Sayyiduna Wakee’ رَحْمَةُ اللّٰهِ عَلَيْه. So, he advised me to leave off [committing] sins since knowledge is a blessing from Allah عَزَّوَجَلَّ, and Allah’s blessings are not bestowed upon a sinner. (Ashi’at-ul-Lam'aat, vol. 1 pp. 188)
Shaykh ‘Allamah ‘Umar Bin Abdul Aziz ‘Aabideen Shami Hanafi رَحْمَةُ اللّٰهِ عَلَيْه has said: Six things weaken [one’s] memory:
1 Eating the leftover of a mouse
2 Leaving a louse alive after catching it
3 Urinating in stagnant water
4 Chewing resin
5 Eating a sour apple
6 Chewing an apple peel. (Mirat-ul-Manajih, vol. 1, pp. 224)
Cure for forgetfulness
Shaykh-ul-Islam, Imam Ibrahim Zarnoji رَحْمَةُ اللّٰهِ عَلَيْه has stated:
1 Using Miswak
2 Using honey
3 Having resin with sugar
4 Having 21 raisins on an empty stomach in the morning strengthen one's memory.
(Ta’leem-ul-Muta’llimTareeq-ut-Ta’llum, pp. 118)
Ways of keeping in mind what you study
There are some ways which can be adopted to commit information to your memory for a longer period of time. For example:
1 One of the ways of committing a point to your memory is to skim through whatever you have studied from the beginning to the end so that its summary gets engraved in your mind.
2 With good intentions, tell what you study to your friends and family. That’s how we can also preserve the treasure of information in our mind for a long period of time.
3 It is a famous quote ‘مَاتَکَرَّرَ تَقَرَّرَ’ The point which is repeated gets engraved in your heart. So, keep on repeating whatever you read.
4 Make a habit of attending scholarly gatherings. By virtue of it, not only you will have a firm grip on knowledge, but you will also get treasure of information.
Telling a point of knowledge to an ineligible person
Remember! Spending money causes decrease in wealth, whereas knowledge is such light that never fades no matter how much you spread it. In fact, its light spreads more and more. However, if you mention the secrets and mysteries of knowledge before an ineligible person, he won’t be able to understand those scholarly points and will misunderstand them. Or, he will pointlessly deny those scholarly points due to his misunderstanding.
Regarding ineligible people, Allamah Abdur Rauf Munavi رَحْمَةُ اللّٰهِ عَلَيْه has stated: These are the people who can’t understand the points of knowledge or don’t act upon them. Therefore, telling such people the point of knowledge is synonymous with rendering the knowledge useless. (Fayz-ul-Qadeer, vol. 1, pp. 70 Taht-al-Hadees 12; summarized)
Sayyiduna ‘Allamah Ali Qaari رَحْمَةُ اللّٰهِ عَلَيْه has narrated: Wasting knowledge means telling a point of knowledge to a such a person who is a seeker of the world and can't understand it, nor does he act upon it. (Mirqat-ul-Mafateeh, vol. 1, pp. 523, Taht-al-Hadees 265)
On the authority of Sayyiduna Kaseer Hadrami رَحْمَةُ اللّٰهِ عَلَيْه, Imam Bayhaqi رَحْمَةُ اللّٰهِ عَلَيْه has narrated: Don’t tell the points of wisdom to foolish people as they will deny you. In addition, do not tell invalid points to the people of wisdom as they will become angry at you. Don’t prevent your knowledge from the person who is eligible to get it. Otherwise, you will become sinner. And don’t tell it to the person who is ineligible because he will consider you as a fool. Indeed, your knowledge has right over you in the same way as your wealth has right over you. (Fayz-ul-Qadeer, vol. 1, pp. 70 Taht-al-Hadees 12; summarized)