Question: From which books is it easier to learn Islam: tafsir books or hadith books?
ANSWER
The most valuable tafsir is Tafsir al-Baydawi. The most valuable hadith books are the Kutub al-Sittah, six books containing collections of hadith. However, it is not possible for us, laymen, to learn our religion from these books. Hadrat Muhammad Hadimi states:

Tafsir is to understand the divine purpose from the divine word. It is not permissible to do tafsir based on one's personal opinions. A hadith-i sharif says: "A person who explains the Qur’an al-karim with his personal views is in error even if his explanation happens to be correct." Hadiths must not be taken directly from the books of hadith. They must be narrated or written after being taken from Islamic scholars' books that deal with fiqh and morals. (Bariqa)

Hadrat Imam-i Sharani stated:
Hadith-i sharifs explained the Qur'an al-karim. Imams of the madhhabs explained hadith-i sharifs, and Islamic scholars explained the words of the imams of the madhhabs. It is impossible to derive rulings from the Qur'an al-karim relating to purity, the number of rak'ats of salats, the words to be said in ruku' and sajda, how to perform Salat al-Eid and Salat al-Janaza, minimum amount required to pay zakat, or obligatory acts of fasting and pilgrimage.

When one said to Hadrat Imran bin Husayn, "Tell me from the Qur'an alone," he answered, "O foolish one!" Can you find in the Qur'an how many rak'ats each salat consists of?" Similarly, when a group of people said to Hadrat 'Umar, "We cannot find in the Qur'an al-karim how many rak'ats we should offer during a journey?" he replied:

Allahu ta'ala sent Muhammad 'alaihis-salam to us. We do that which we cannot find in the Qur'an al-karim as we saw how it was done by the Messenger of Allah. He performed four-rak'at obligatory salats as two rak'ats during a journey, so we do likewise. (Mizan-ul-kubra)

Hadrat Abd al-Ghani al-Nablusi says:
Profound scholars derived the rulings pertaining to jurisprudence (fiqh) from Qur'anic verses and hadith-i sharifs. They can be learnt only from fiqh books, yet it would be an act of voluntary worship to attempt to learn fiqh from books of tafsîr while there are the books of fiqh, and it would not be permissible to do something voluntary by reading books of tafsir, instead of reading books of fiqh, which is an act of fard al-'ayn (that which is incumbent upon every individual Muslim). Besides, it would be impossible for non-mujtahids to acquire knowledge of fiqh from books of tafsir. Scholars of the 72 (heretical) groups who it had been stated would go to Hell, deviated from the right path as a result of their misinterpretations from books of tafsir. It would be a disaster for the layman to read tafsir books that have caused scholars to lose their bearings. To be able to understand tafsir books, one must learn 20 main branches of knowledge including their 80 sub-branches.

A person who wants to learn true meanings of the Qur'an al-karim must read Islamic scholars' books that deal with theology (kalam), jurisprudence (fiqh), and morals. (Hadiqa)

Allahu ta’ala declares in the 44th verse of Surat an-Nahl, “Explain [make bayan] to humans what I send down for them.” Bayan means to express the verses revealed by Allahu ta'ala in other terms, in a different way. If the scholars among the Ummah had been able to make bayan of verses and to interpret succinct ones, Allahu ta’ala would have said to His Prophet, "Tell them what is sent to you through the Angel," and He would not have commanded him to make bayan.

If the Messenger of Allah had not explained what had been declared briefly in the Qur’an al-karim and if the imams of the madhhabs had not explained what had been communicated symbolically, none of us could have understood them. The imams of madhhabs, who were great scholars, explained hadith-i sharifs. These scholars are inheritors of the Messenger of Allah.

As we have to believe and confirm all the revelations that the Messenger of Allah brought even if we cannot understand their ultimate divine reasons and evidences, so we have to believe and confirm the knowledge conveyed from our imams of madhhabs, even if we do not understand their evidences.

Despite the fact that there are different, even opposite principles in the religions of all prophets, we, Muslims, have to believe and acknowledge all of them. The case is the same with the madhhabs.

Non-mujtahids have to believe and acknowledge all the four madhhabs though they may see that there are differences between them. A non-mujtahid’s finding a madhhab as erroneous does not show that the madhhab is erroneous. Instead, it shows that he/she understands little and that he/she himself/herself is erroneous. (Mizan-ul-Kubra)