Explanation of the definition:

Our saying, “knowledge,” rather than “certain knowledge,” is because fiqh may consist either of certain knowledge or of probable knowledge. Not every issue of fiqh is decisively known; rather, it contains many matters based on probability. This is common in issues of independent legal reasoning, in which a person cannot attain the degree of certainty. Yet Allah does not burden any soul beyond its capacity.

Thus, we say “knowledge” so that it encompasses both certainty and probability.

And our saying, “practical,” excludes doctrinal rulings. They therefore do not fall under the technical designation of fiqh, even though they do fall within the Sacred Law.

And our saying, “based on their detailed evidences,” excludes the principles of fiqh, because the study of the principles of fiqh concerns the general evidences of fiqh; a detailed issue may only be mentioned by way of example.

It is understood from our saying, “based on their evidences,” that one who merely follows another’s opinion is not a jurist, because he does not know the rulings through their evidences. At most, he simply repeats them as they appear in the book. Ibn ʿAbd al-Barr reported scholarly consensus on this. (1)

From this we recognize the importance of knowing the evidence, and that the student of knowledge must learn issues together with their evidences. This is what will save him before Allah, for Allah will say to him on the Day of Resurrection: “What answer did you give to the messengers?” [al-Qaṣaṣ: 65] He will not say: “What answer did you give to such-and-such an author,”