Don't be Sad
Beneficial knowledge and fruitless knowledge
(And those who have been bestowed with knowledge and faith will say: 'indeed you have stayed according to the Decree of Allah, until the Day of Resurrection, but you knew not. (Qur'an 30: 56)
There is knowledge that is useful and there is knowledge that is harmful. As for the knowledge that is useful, the believer's faith strengthens as a result of it; on the other hand, the disbeliever does not reap any benefit whatsoever from gaining this kind of knowledge, though the information acquired is the same, the results are very different. Allah says of His enemies:
(They know only the outside appearance of the life of the world [i.e. the matters of their livelihood, like irrigation or sowing or reaping, etc.], and they are heedless of the Hereafter) (Qur'an 30: 7)
(Nay, they have no knowledge of the Hereafter Nay, they are in doubt about it. Nay, they are blind about it.) (Qur'an 27: 66)
(That is what they could reach of knowledge.) (Qur'an 53: 30)
(And recite [O' Muhammad] to them the story of him to whom we gave Our Aayaat [proofs, evidences, verses, lessons, signs, revelations, etc.], but he threw them away so Satan followed him up, and he became of those who went astray. And had we willed, we would surely have elevated him therewith but he clung to the earth and followed his own vain desire. So his description is the description of a dog if you drive him away, he lolls his tongue out, or if you leave him alone, he (still) lolls his tongue out. Such is the description of the people who reject Our Aayaat [proofs, evidences, verses, lessons, signs, revelations, etc]. So relate the stories, perhaps they may reflect) (Qur'an 7: 175-176)
Allah said about the Jews and their knowledge of the truth:
(The likeness of those who were entrusted with the Torah, but who subsequently failed in those [obligations], is as the likeness of a donkey who carries huge burdens of books [but understands nothing from them]. How bad is the example of people who deny the Aayaat [proofs, evidences, signs, verses, etc.] of Allah. (Qur'an 62: 5)
They knew the truth from the Torah, yet they were not guided by it. They distorted its words, and if that failed to work, they distorted the meanings of the words. How could people who treated knowledge in this despicable manner ever have found happiness? Lt was certainly not possible in their case, for they always tried to eradicate the truth using any means at their disposal.
(…but they preferred blindness to guidance……) (Qur'an 41: 17)
(And of their saying: 'Our hearts are wrapped (with coverings, i.e.
We do not understand what the Messengers say)' ----- may Allah has set a seal upon their hearts because of their disbelief so they believe not but a little. (Qur'an 4: I55)
There are thousands, perhaps millions of books in the Library of Congress in Washington. There are books that deal with every century, every people, every nation, and every culture. Yet who owns this venerable library; a nation that disbelieves in its Lord, a nation whose knowledge passes not the bounds of the tangible, material world. As for what is beyond the material world, they hear not, see not, feel not, nor do they understand.
(And we had assigned them the [faculties of] hearing, seeing, and hearts, but their hearing, seeing and their hearts availed them nothing.)
(Qur'an 46: 26)
The likeness between the truth and the disbeliever's aversion to it is as follows: The water is pure and sweet; however, the person drinking it feels a bitter taste.
(How many clear Aayaat [proofs, evidences, verses, lessons, signs, revelations, etc.] We gave them.)
(Qur'an 2: 211)
(And never an Aayah [sign] comes to them from the Aayaat [proofs, evidences, verses, lessons, signs, revelations, etc.] of their Lord, but that they have been turning away from it) (Qur'an 6: 4)