In the name of Allah, the Most Compassionate, the Most Merciful.
All praise is due to Allah; we praise Him, seek His help, and ask His forgiveness. We seek refuge in Allah from the evils within ourselves and from our misdeeds. Whomever Allah guides, none can misguide, and whomever He allows to stray, none can guide. I bear witness that there is no deity worthy of worship except Allah alone, without partner, and I bear witness that Muhammad is His servant and messenger. May Allah bless and grant peace to him, to his family, his Companions, and to all who follow them with excellence until the Day of Judgment.
To proceed:1
This is an introduction to the science of ḥadith terminology.
Muṣṭalaḥ (terminology) is the discipline by which the states of both the narrator and what is narrated are known, in terms of acceptance or rejection.
The benefit of this discipline is to purify the prophetic evidences and remove from them whatever taints them—such as weak reports and the like—so that they can be used as proof. For whoever seeks to derive rulings from the sunnah needs two things:
1 – Certainty that the report is authentically traced back to the Prophet (peace and blessings be upon him).
2 – Certainty that its wording truly indicates the intended ruling.
Thus, caring for the Prophetic Sunnah is of great importance, for upon it rests something even more crucial: the duties Allah has laid upon His servants in matters of belief, worship, character, and beyond.