Ḥadīth scholars excelled in continuing the efforts of their precedents by; completing their unfinished work, making up for missed ones, or by fathers completing their sons’ unfinished work; a noble service from the eldest to the books of the youngest. The first scholar known for this is Thābit bin Ḥazm al-Saraqusṭī who completed his son’s Qāssim unfinished book (al-Dalāʾil), when Qāssim died before completing it. This book is not only considered as the most valuable one among Gharīb al-Ḥadīth books in Andalusīya but, as one of the most important books in Gharīb al-Ḥadīth in general. The author based his book al-Dalāīyl on the previous work of Abī Ūbayd al-Qāssim bin Sallām and Ibn Qutayba’s known books in Gharīb al-Ḥadīth, adding to what they’ve missed. He followed their methodology starting with al-Ḥadīth al-Marfoūʿ, followed by al-Mawqūf, then al-Maqṭūʿ, and maintained the precursor’s approach in referencing. Several scholars benefited enormously from this book and classified it among their valued resources. Thābit bin Qāssim bin Thābit – the grandson – was the key narrator for this book, assisting in its spread.